Windows String Processing - C++ Samples

#include <iostream>
#include <string>
#include <vector>
#include <sstream>
#include <algorithm>
#include <cctype>
#include <chrono>
#include <regex>
#include <iomanip>
#include <codecvt>
#include <locale>
#include <memory>

// 1. Basic string concatenation methods
void BasicConcatenation() {
    std::cout << "=== Basic String Concatenation ===" << std::endl;

    // Method 1: Using + operator
    std::string str1 = "Hello";
    std::string str2 = "World";
    std::string result1 = str1 + " " + str2 + "!";
    std::cout << "Using + operator: " << result1 << std::endl;

    // Method 2: Using append()
    std::string result2;
    result2.append(str1);
    result2.append(" ");
    result2.append(str2);
    result2.append("!");
    std::cout << "Using append(): " << result2 << std::endl;

    // Method 3: Using string stream
    std::ostringstream oss;
    oss << str1 << " " << str2 << "!";
    std::string result3 = oss.str();
    std::cout << "Using stringstream: " << result3 << std::endl;

    // Method 4: Using push_back for character by character
    std::string result4;
    std::string combined = str1 + " " + str2 + "!";
    for (char c : combined) {
        result4.push_back(c);
    }
    std::cout << "Using push_back: " << result4 << std::endl;
}

// 2. Performance comparison of concatenation methods
void PerformanceComparison() {
    std::cout << "\n=== Concatenation Performance Comparison ===" << std::endl;

    const int ITERATIONS = 10000;
    const std::string BASE_STRING = "Hello";
    const std::string ADD_STRING = " World";

    // Method 1: Using + operator
    auto start = std::chrono::high_resolution_clock::now();
    std::string result1;
    for (int i = 0; i < ITERATIONS; i++) {
        result1 = result1 + ADD_STRING;
    }
    auto end = std::chrono::high_resolution_clock::now();
    auto duration1 = std::chrono::duration_cast<std::chrono::microseconds>(end - start);
    std::cout << "Using + operator: " << duration1.count() << " μs" << std::endl;

    // Method 2: Using append()
    start = std::chrono::high_resolution_clock::now();
    std::string result2;
    for (int i = 0; i < ITERATIONS; i++) {
        result2.append(ADD_STRING);
    }
    end = std::chrono::high_resolution_clock::now();
    auto duration2 = std::chrono::duration_cast<std::chrono::microseconds>(end - start);
    std::cout << "Using append(): " << duration2.count() << " μs" << std::endl;

    // Method 3: Using stringstream
    start = std::chrono::high_resolution_clock::now();
    std::ostringstream oss;
    oss << BASE_STRING;
    for (int i = 0; i < ITERATIONS; i++) {
        oss << ADD_STRING;
    }
    std::string result3 = oss.str();
    end = std::chrono::high_resolution_clock::now();
    auto duration3 = std::chrono::duration_cast<std::chrono::microseconds>(end - start);
    std::cout << "Using stringstream: " << duration3.count() << " μs" << std::endl;

    // Method 4: Using reserve() + append() (most efficient for large concatenations)
    start = std::chrono::high_resolution_clock::now();
    std::string result4;
    result4.reserve(BASE_STRING.length() + ADD_STRING.length() * ITERATIONS);
    result4 = BASE_STRING;
    for (int i = 0; i < ITERATIONS; i++) {
        result4.append(ADD_STRING);
    }
    end = std::chrono::high_resolution_clock::now();
    auto duration4 = std::chrono::duration_cast<std::chrono::microseconds>(end - start);
    std::cout << "Using reserve() + append(): " << duration4.count() << " μs" << std::endl;

    // Performance summary
    std::cout << "\nPerformance summary (μs):" << std::endl;
    std::cout << "+ operator: " << duration1.count() << std::endl;
    std::cout << "append(): " << duration2.count() << std::endl;
    std::cout << "stringstream: " << duration3.count() << std::endl;
    std::cout << "reserve + append: " << duration4.count() << " (fastest)" << std::endl;
}

// 3. Advanced concatenation with formatting
void AdvancedConcatenation() {
    std::cout << "\n=== Advanced Concatenation with Formatting ===" << std::endl;

    // Format integers, floats, and other types
    int age = 25;
    double height = 1.75;
    std::string name = "Alice";

    std::ostringstream formatted;
    formatted << "Name: " << name << ", Age: " << age << ", Height: "
               << std::fixed << std::setprecision(2) << height << "m";
    std::cout << "Formatted string: " << formatted.str() << std::endl;

    // Using format-style placeholders
    std::string templateStr = "User {0} is {1} years old and {2}m tall";
    std::string formattedStr = FormatString(templateStr, {name, std::to_string(age), std::to_string(height)});
    std::cout << "Custom formatted: " << formattedStr << std::endl;

    // Padding and alignment
    std::vector<std::string> names = {"Alice", "Bob", "Charlie", "David"};
    std::vector<int> scores = {95, 87, 92, 78};

    std::cout << "\nFormatted table:" << std::endl;
    for (size_t i = 0; i < names.size(); i++) {
        std::ostringstream row;
        row << std::setw(10) << std::left << names[i]
            << " | Score: " << std::setw(3) << std::right << scores[i];
        std::cout << row.str() << std::endl;
    }
}

// Helper function for custom string formatting
std::string FormatString(const std::string& templateStr, const std::vector<std::string>& args) {
    std::string result = templateStr;
    for (size_t i = 0; i < args.size(); i++) {
        std::string placeholder = "{" + std::to_string(i) + "}";
        size_t pos = result.find(placeholder);
        if (pos != std::string::npos) {
            result.replace(pos, placeholder.length(), args[i]);
        }
    }
    return result;
}

// 4. String splitting by different delimiters
void StringSplitting() {
    std::cout << "\n=== String Splitting ===" << std::endl;

    // Basic comma-separated splitting
    std::string csv = "apple,banana,cherry,date,elderberry";
    std::vector<std::string> fruits = SplitString(csv, ",");

    std::cout << "CSV splitting - Original: " << csv << std::endl;
    std::cout << "Results: ";
    for (const auto& fruit : fruits) {
        std::cout << "[" << fruit << "] ";
    }
    std::cout << std::endl;

    // Split by whitespace
    std::string sentence = "The quick brown fox jumps over the lazy dog";
    std::vector<std::string> words = SplitString(sentence, " ");

    std::cout << "\nWhitespace splitting - Original: " << sentence << std::endl;
    std::cout << "Words (" << words.size() << "): ";
    for (const auto& word : words) {
        std::cout << word << " ";
    }
    std::cout << std::endl;

    // Split with multiple character delimiter
    std::string data = "key1=value1;key2=value2;key3=value3";
    std::vector<std::string> pairs = SplitString(data, ";");

    std::cout << "\nMultiple delimiter splitting - Original: " << data << std::endl;
    for (const auto& pair : pairs) {
        std::cout << "Pair: " << pair << std::endl;
        // Further split by '='
        std::vector<std::string> keyValue = SplitString(pair, "=");
        if (keyValue.size() == 2) {
            std::cout << "  Key: " << keyValue[0] << ", Value: " << keyValue[1] << std::endl;
        }
    }

    // Split using stringstream (better for whitespace handling)
    std::stringstream ss(sentence);
    std::vector<std::string> streamWords;
    std::string word;
    while (ss >> word) {
        streamWords.push_back(word);
    }

    std::cout << "\nStringStream splitting - Words (" << streamWords.size() << "): ";
    for (const auto& w : streamWords) {
        std::cout << w << " ";
    }
    std::cout << std::endl;

    // Split with empty token handling
    std::string path = "/usr//local/bin/";
    std::vector<std::string> pathParts = SplitStringKeepEmpty(path, "/");

    std::cout << "\nPath splitting with empty tokens: " << path << std::endl;
    for (size_t i = 0; i < pathParts.size(); i++) {
        std::cout << "  Part " << i << ": [" << pathParts[i] << "]" << std::endl;
    }
}

// Basic string splitting function
std::vector<std::string> SplitString(const std::string& str, const std::string& delimiter) {
    std::vector<std::string> result;
    size_t start = 0;
    size_t end = str.find(delimiter);

    while (end != std::string::npos) {
        if (start != end) { // Avoid empty strings
            result.push_back(str.substr(start, end - start));
        }
        start = end + delimiter.length();
        end = str.find(delimiter, start);
    }

    if (start < str.length()) {
        result.push_back(str.substr(start));
    }

    return result;
}

// String splitting function that keeps empty tokens
std::vector<std::string> SplitStringKeepEmpty(const std::string& str, const std::string& delimiter) {
    std::vector<std::string> result;
    size_t start = 0;
    size_t end = str.find(delimiter);

    while (end != std::string::npos) {
        result.push_back(str.substr(start, end - start));
        start = end + delimiter.length();
        end = str.find(delimiter, start);
    }

    result.push_back(str.substr(start));
    return result;
}

// 5. Advanced splitting with multiple delimiters
void AdvancedSplitting() {
    std::cout << "\n=== Advanced Splitting ===" << std::endl;

    // Split by any whitespace character
    std::string text = "Hello\tWorld\nThis is a  test";
    std::vector<std::string> whitespaceWords = SplitByWhitespace(text);

    std::cout << "Original: '" << text << "'" << std::endl;
    std::cout << "Split by whitespace: ";
    for (const auto& word : whitespaceWords) {
        std::cout << "[" << word << "] ";
    }
    std::cout << std::endl;

    // Split by multiple specific delimiters
    std::string data = "name=John,age=25;city=New York|country=USA";
    std::vector<std::string> delimiters = {",", ";", "|"};
    std::vector<std::string> parts = SplitByMultipleDelimiters(data, delimiters);

    std::cout << "\nMulti-delimiter splitting:" << std::endl;
    std::cout << "Original: " << data << std::endl;
    for (const auto& part : parts) {
        std::cout << "  [" << part << "]" << std::endl;
    }

    // Split and limit number of splits
    std::string limitedText = "one,two,three,four,five";
    std::vector<std::string> limitedParts = SplitStringN(limitedText, ",", 3);

    std::cout << "\nLimited splitting (max 3 parts):" << std::endl;
    std::cout << "Original: " << limitedText << std::endl;
    for (const auto& part : limitedParts) {
        std::cout << "  [" << part << "]" << std::endl;
    }
}

// Split by any whitespace
std::vector<std::string> SplitByWhitespace(const std::string& str) {
    std::vector<std::string> result;
    std::istringstream iss(str);
    std::string word;
    while (iss >> word) {
        result.push_back(word);
    }
    return result;
}

// Split by multiple delimiters
std::vector<std::string> SplitByMultipleDelimiters(const std::string& str,
                                                  const std::vector<std::string>& delimiters) {
    std::vector<std::string> result;
    if (delimiters.empty()) {
        result.push_back(str);
        return result;
    }

    // Use the first delimiter for initial split
    std::vector<std::string> parts = SplitString(str, delimiters[0]);

    // For each remaining delimiter, split all current parts
    for (size_t i = 1; i < delimiters.size(); i++) {
        std::vector<std::string> newParts;
        for (const auto& part : parts) {
            std::vector<std::string> splitParts = SplitString(part, delimiters[i]);
            newParts.insert(newParts.end(), splitParts.begin(), splitParts.end());
        }
        parts = newParts;
    }

    return parts;
}

// Split string with maximum number of splits
std::vector<std::string> SplitStringN(const std::string& str, const std::string& delimiter, int maxSplits) {
    std::vector<std::string> result;
    size_t start = 0;
    int splits = 0;
    size_t end = str.find(delimiter);

    while (end != std::string::npos && splits < maxSplits) {
        result.push_back(str.substr(start, end - start));
        start = end + delimiter.length();
        end = str.find(delimiter, start);
        splits++;
    }

    // Add the remaining part
    result.push_back(str.substr(start));
    return result;
}

// 6. Join operations (reverse of splitting)
void StringJoining() {
    std::cout << "\n=== String Joining ===" << std::endl;

    std::vector<std::string> words = {"The", "quick", "brown", "fox"};
    std::vector<std::string> numbers = {"1", "2", "3", "4", "5"};

    // Join with space
    std::string sentence = JoinStrings(words, " ");
    std::cout << "Joined with space: " << sentence << std::endl;

    // Join with comma and space
    std::string csv = JoinStrings(words, ", ");
    std::cout << "CSV style: " << csv << std::endl;

    // Join with prefix and suffix
    std::string bracketed = JoinWithPrefixSuffix(numbers, "[", "]", " + ");
    std::cout << "Math expression: " << bracketed << std::endl;

    // Conditional joining (skip empty strings)
    std::vector<std::string> mixed = {"Hello", "", "World", "", "C++"};
    std::string cleanJoined = JoinSkipEmpty(mixed, " ");
    std::cout << "Skip empty: " << cleanJoined << std::endl;

    // Join with limits
    std::vector<std::string> manyWords = {"These", "are", "many", "words", "to", "join"};
    std::string limited = JoinWithLimit(manyWords, ", ", 3, "...");
    std::cout << "Limited join: " << limited << std::endl;
}

// Basic join function
std::string JoinStrings(const std::vector<std::string>& strings, const std::string& delimiter) {
    if (strings.empty()) {
        return "";
    }

    std::string result = strings[0];
    for (size_t i = 1; i < strings.size(); i++) {
        result += delimiter + strings[i];
    }
    return result;
}

// Join with prefix and suffix around each element
std::string JoinWithPrefixSuffix(const std::vector<std::string>& strings,
                               const std::string& prefix, const std::string& suffix,
                               const std::string& delimiter) {
    if (strings.empty()) {
        return "";
    }

    std::string result = prefix + strings[0] + suffix;
    for (size_t i = 1; i < strings.size(); i++) {
        result += delimiter + prefix + strings[i] + suffix;
    }
    return result;
}

// Join skipping empty strings
std::string JoinSkipEmpty(const std::vector<std::string>& strings, const std::string& delimiter) {
    std::vector<std::string> nonEmpty;
    for (const auto& str : strings) {
        if (!str.empty()) {
            nonEmpty.push_back(str);
        }
    }
    return JoinStrings(nonEmpty, delimiter);
}

// Join with limit on number of elements
std::string JoinWithLimit(const std::vector<std::string>& strings,
                        const std::string& delimiter, int maxElements,
                        const std::string& suffix) {
    if (strings.empty()) {
        return "";
    }

    std::string result = strings[0];
    for (int i = 1; i < std::min(maxElements, (int)strings.size()); i++) {
        result += delimiter + strings[i];
    }

    if (strings.size() > static_cast<size_t>(maxElements)) {
        result += delimiter + suffix;
    }

    return result;
}

// 7. String parsing and extraction
void StringParsing() {
    std::cout << "\n=== String Parsing and Extraction ===" << std::endl;

    // Extract numbers from string
    std::string text1 = "The temperature is 23.5 degrees and humidity is 45%";
    std::vector<double> numbers = ExtractNumbers(text1);

    std::cout << "Original: " << text1 << std::endl;
    std::cout << "Extracted numbers: ";
    for (double num : numbers) {
        std::cout << num << " ";
    }
    std::cout << std::endl;

    // Extract words with specific criteria
    std::string text2 = "Hello world! This is a C++ string processing example.";
    std::vector<std::string> longWords = ExtractWordsLongerThan(text2, 4);

    std::cout << "\nOriginal: " << text2 << std::endl;
    std::cout << "Words longer than 4 characters: ";
    for (const auto& word : longWords) {
        std::cout << word << " ";
    }
    std::cout << std::endl;

    // Extract email addresses
    std::string emailText = "Contact us at support@example.com or admin@company.org";
    std::vector<std::string> emails = ExtractEmails(emailText);

    std::cout << "\nEmail extraction:" << std::endl;
    std::cout << "Original: " << emailText << std::endl;
    for (const auto& email : emails) {
        std::cout << "Found email: " << email << std::endl;
    }

    // Parse key-value pairs
    std::string configText = "name=John Doe; age=30; city=New York; country=USA";
    std::map<std::string, std::string> config = ParseKeyValuePairs(configText, ";", "=");

    std::cout << "\nKey-value parsing:" << std::endl;
    std::cout << "Original: " << configText << std::endl;
    for (const auto& [key, value] : config) {
        std::cout << key << " = " << value << std::endl;
    }
}

// Extract all numbers from string
std::vector<double> ExtractNumbers(const std::string& str) {
    std::vector<double> numbers;
    std::regex numberRegex(R"([-+]?\d*\.?\d+)");
    std::sregex_iterator iter(str.begin(), str.end(), numberRegex);
    std::sregex_iterator end;

    for (; iter != end; ++iter) {
        numbers.push_back(std::stod(iter->str()));
    }

    return numbers;
}

// Extract words longer than specified length
std::vector<std::string> ExtractWordsLongerThan(const std::string& str, int minLength) {
    std::vector<std::string> result;
    std::regex wordRegex(R"(\b\w+\b)");
    std::sregex_iterator iter(str.begin(), str.end(), wordRegex);
    std::sregex_iterator end;

    for (; iter != end; ++iter) {
        std::string word = iter->str();
        if (word.length() > static_cast<size_t>(minLength)) {
            result.push_back(word);
        }
    }

    return result;
}

// Extract email addresses
std::vector<std::string> ExtractEmails(const std::string& str) {
    std::vector<std::string> emails;
    std::regex emailRegex(R"([\w\.-]+@[\w\.-]+\.[a-zA-Z]{2,})");
    std::sregex_iterator iter(str.begin(), str.end(), emailRegex);
    std::sregex_iterator end;

    for (; iter != end; ++iter) {
        emails.push_back(iter->str());
    }

    return emails;
}

// Parse key-value pairs
std::map<std::string, std::string> ParseKeyValuePairs(const std::string& str,
                                                   const std::string& pairDelimiter,
                                                   const std::string& kvDelimiter) {
    std::map<std::string, std::string> result;
    std::vector<std::string> pairs = SplitString(str, pairDelimiter);

    for (const auto& pair : pairs) {
        std::vector<std::string> keyValue = SplitString(pair, kvDelimiter);
        if (keyValue.size() == 2) {
            // Trim whitespace
            std::string key = Trim(keyValue[0]);
            std::string value = Trim(keyValue[1]);
            result[key] = value;
        }
    }

    return result;
}

// Trim whitespace from string
std::string Trim(const std::string& str) {
    size_t start = str.find_first_not_of(" \t\n\r");
    if (start == std::string::npos) {
        return "";
    }

    size_t end = str.find_last_not_of(" \t\n\r");
    return str.substr(start, end - start + 1);
}

// 8. Unicode and UTF-8 string handling
void UnicodeHandling() {
    std::cout << "\n=== Unicode and UTF-8 Handling ===" << std::endl;

    // UTF-8 string processing
    std::string utf8Text = u8"Hello 世界 🌍 C++";
    std::cout << "UTF-8 text: " << utf8Text << std::endl;
    std::cout << "UTF-8 byte length: " << utf8Text.length() << std::endl;

    // Wide string conversion
    std::wstring wideText = L"Hello World C++";
    std::wstring_convert<std::codecvt_utf8<wchar_t>> converter;
    std::string converted = converter.to_bytes(wideText);
    std::wstring backConverted = converter.from_bytes(converted);

    std::cout << "Wide string: " << wideText.length() << " characters" << std::endl;
    std::cout << "Converted to UTF-8: " << converted << std::endl;
    std::cout << "Converted back: " << backConverted.length() << " characters" << std::endl;

    // Count Unicode characters (simplified approach)
    std::string unicodeText = u8"Привет мир 🌍";
    int charCount = CountUnicodeCharacters(unicodeText);
    std::cout << "Unicode text: " << unicodeText << std::endl;
    std::cout << "Unicode character count: " << charCount << std::endl;

    // Case conversion for Unicode
    std::string lowerText = "hello world";
    std::string upperText = ToUpper(lowerText);
    std::string backToLower = ToLower(upperText);

    std::cout << "\nCase conversion:" << std::endl;
    std::cout << "Original: " << lowerText << std::endl;
    std::cout << "Upper: " << upperText << std::endl;
    std::cout << "Lower: " << backToLower << std::endl;
}

// Count Unicode characters (simplified UTF-8)
int CountUnicodeCharacters(const std::string& utf8String) {
    int count = 0;
    for (size_t i = 0; i < utf8String.length(); ) {
        unsigned char c = utf8String[i];

        if (c < 0x80) {
            // ASCII character (1 byte)
            i += 1;
        } else if ((c >> 5) == 0x6) {
            // 2-byte UTF-8 sequence
            i += 2;
        } else if ((c >> 4) == 0xE) {
            // 3-byte UTF-8 sequence
            i += 3;
        } else if ((c >> 3) == 0x1E) {
            // 4-byte UTF-8 sequence
            i += 4;
        } else {
            // Invalid UTF-8, skip this byte
            i += 1;
        }
        count++;
    }
    return count;
}

// Convert to uppercase (ASCII only for simplicity)
std::string ToUpper(const std::string& str) {
    std::string result = str;
    for (char& c : result) {
        c = std::toupper(static_cast<unsigned char>(c));
    }
    return result;
}

// Convert to lowercase (ASCII only for simplicity)
std::string ToLower(const std::string& str) {
    std::string result = str;
    for (char& c : result) {
        c = std::tolower(static_cast<unsigned char>(c));
    }
    return result;
}

int main() {
    std::cout << "=== C++ Windows String Processing ===" << std::endl;
    std::cout << "Demonstrating comprehensive string manipulation techniques\n" << std::endl;

    try {
        // Run all string processing examples
        BasicConcatenation();
        PerformanceComparison();
        AdvancedConcatenation();
        StringSplitting();
        AdvancedSplitting();
        StringJoining();
        StringParsing();
        UnicodeHandling();

        std::cout << "\nAll string processing examples completed successfully!" << std::endl;

    } catch (const std::exception& e) {
        std::cerr << "Unexpected error: " << e.what() << std::endl;
        return 1;
    }

    return 0;
}

#include <iostream>
#include <string>
#include <regex>
#include <vector>
#include <map>
#include <sstream>
#include <iomanip>
#include <algorithm>

// 1. Basic regex operations
void BasicRegexOperations() {
    std::cout << "=== Basic Regex Operations ===" << std::endl;

    // Simple pattern matching
    std::string text = "Hello World 123";
    std::regex pattern(R"(\w+)"); // Match word characters

    std::cout << "Text: " << text << std::endl;
    std::cout << "Pattern: \w+ (word characters)" << std::endl;

    std::sregex_iterator iter(text.begin(), text.end(), pattern);
    std::sregex_iterator end;

    std::cout << "Matches found:" << std::endl;
    for (; iter != end; ++iter) {
        std::smatch match = *iter;
        std::cout << "  " << match.str() << " at position " << match.position() << std::endl;
    }

    // Check if pattern matches entire string
    std::regex exactPattern(R"(Hello\s+World\s+\d+)");
    bool exactMatch = std::regex_match(text, exactPattern);
    std::cout << "\nExact match (Hello World 123): " << (exactMatch ? "Yes" : "No") << std::endl;

    // Search for pattern in string
    std::regex searchPattern(R"(\d+)");
    bool found = std::regex_search(text, searchPattern);
    std::cout << "Search for digits: " << (found ? "Found" : "Not found") << std::endl;
}

// 2. Pattern matching with groups
void PatternMatchingWithGroups() {
    std::cout << "\n=== Pattern Matching with Groups ===" << std::endl;

    // Extract date components
    std::string dateText = "Date: 2023-12-25, Time: 14:30:45";
    std::regex datePattern(R"(Date: (\d{4})-(\d{2})-(\d{2}))");

    std::smatch dateMatch;
    if (std::regex_search(dateText, dateMatch, datePattern)) {
        std::cout << "Date text: " << dateText << std::endl;
        std::cout << "Full match: " << dateMatch[0].str() << std::endl;
        std::cout << "Year: " << dateMatch[1].str() << std::endl;
        std::cout << "Month: " << dateMatch[2].str() << std::endl;
        std::cout << "Day: " << dateMatch[3].str() << std::endl;
    }

    // Extract email components
    std::string email = "user.name@domain.com";
    std::regex emailPattern(R"((\w+[\.\w]*\w+)@(\w+[\.\w]*\w+)\.(\w+))");

    std::smatch emailMatch;
    if (std::regex_match(email, emailMatch, emailPattern)) {
        std::cout << "\nEmail: " << email << std::endl;
        std::cout << "Username: " << emailMatch[1].str() << std::endl;
        std::cout << "Domain: " << emailMatch[2].str() << std::endl;
        std::cout << "TLD: " << emailMatch[3].str() << std::endl;
    }

    // Extract URL components
    std::string url = "https://www.example.com/path/to/page?param1=value1&param2=value2";
    std::regex urlPattern(R"((https?://)([^/]+)([^?]*)(\?(.*))?)");

    std::smatch urlMatch;
    if (std::regex_match(url, urlMatch, urlPattern)) {
        std::cout << "\nURL: " << url << std::endl;
        std::cout << "Protocol: " << urlMatch[1].str() << std::endl;
        std::cout << "Domain: " << urlMatch[2].str() << std::endl;
        std::cout << "Path: " << urlMatch[3].str() << std::endl;
        std::cout << "Query string: " << urlMatch[5].str() << std::endl;
    }
}

// 3. Text validation patterns
void TextValidation() {
    std::cout << "\n=== Text Validation Patterns ===" << std::endl;

    // Email validation
    std::vector<std::string> emails = {
        "user@example.com",
        "user.name@domain.co.uk",
        "user123@test-domain.org",
        "invalid.email@",
        "@missing-user.com",
        "user@.invalid-domain"
    };

    std::regex emailPattern(
        R"(^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+.[a-zA-Z]{2,}$)"
    );

    std::cout << "Email validation:" << std::endl;
    for (const auto& email : emails) {
        bool isValid = std::regex_match(email, emailPattern);
        std::cout << email << " - " << (isValid ? "Valid" : "Invalid") << std::endl;
    }

    // Phone number validation
    std::vector<std::string> phones = {
        "123-456-7890",
        "(123) 456-7890",
        "+1 (123) 456-7890",
        "123.456.7890",
        "1234567890",
        "invalid-phone"
    };

    std::regex phonePattern(
        R"(^\+?1?[.-\s]?\(?\d{3}\)?[.-\s]?\d{3}[.-\s]?\d{4}$)"
    );

    std::cout << "\nPhone number validation:" << std::endl;
    for (const auto& phone : phones) {
        bool isValid = std::regex_match(phone, phonePattern);
        std::cout << phone << " - " << (isValid ? "Valid" : "Invalid") << std::endl;
    }

    // Password strength validation
    std::vector<std::string> passwords = {
        "password",           // Weak: lowercase only
        "Password123",        // Medium: mixed case, numbers
        "P@ssw0rd!123",       // Strong: mixed case, numbers, special chars
        "Short1!",            // Weak: too short
        "VeryLongPasswordWithNoNumbersOrSpecialChars", // Medium: long but no variety
        "Str0ng#P@ss"         // Strong: good mix
    };

    std::regex strongPasswordPattern(
        R"^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)(?=.*[@$!%*?&])[A-Za-z\d@$!%*?&]{8,}$)"
    );

    std::cout << "\nPassword strength validation:" << std::endl;
    for (const auto& password : passwords) {
        bool isStrong = std::regex_match(password, strongPasswordPattern);
        std::cout << "  '" << password << "' - " << (isStrong ? "Strong" : "Weak/Invalid") << std::endl;
    }
}

// 4. Text extraction and replacement
void TextExtractionAndReplacement() {
    std::cout << "\n=== Text Extraction and Replacement ===" << std::endl;

    std::string content = R"(
        Contact Information:
        Email: john.doe@example.com
        Phone: (555) 123-4567
        Address: 123 Main St, City, State 12345
        Website: https://www.example.com
        Additional contact: jane.smith@another-domain.org
    )";

    std::cout << "Original content:" << content << std::endl;

    // Extract all emails
    std::regex emailPattern(R"([\w\.-]+@[\w\.-]+\.[a-zA-Z]{2,})");
    std::vector<std::string> extractedEmails;

    std::sregex_iterator emailIter(content.begin(), content.end(), emailPattern);
    std::sregex_iterator emailEnd;

    std::cout << "\nExtracted emails:" << std::endl;
    for (; emailIter != emailEnd; ++emailIter) {
        std::string email = emailIter->str();
        extractedEmails.push_back(email);
        std::cout << "  " << email << std::endl;
    }

    // Extract phone numbers
    std::regex phonePattern(R"(\(\d{3}\)\s*\d{3}[-\s]?\d{4})");
    std::vector<std::string> extractedPhones;

    std::sregex_iterator phoneIter(content.begin(), content.end(), phonePattern);
    std::sregex_iterator phoneEnd;

    std::cout << "\nExtracted phone numbers:" << std::endl;
    for (; phoneIter != phoneEnd; ++phoneIter) {
        std::string phone = phoneIter->str();
        extractedPhones.push_back(phone);
        std::cout << "  " << phone << std::endl;
    }

    // Replace emails with placeholder
    std::string replacedContent = std::regex_replace(
        content, emailPattern, "[EMAIL PROTECTED]"
    );

    std::cout << "\nContent after email replacement:" << std::endl;
    std::cout << replacedContent << std::endl;

    // Replace phone numbers with formatted version
    std::string formattedContent = std::regex_replace(
        content,
        phonePattern,
        "Phone: $1" // $1 captures the entire phone number group
    );

    std::cout << "\nContent with formatted phones:" << std::endl;
    std::cout << formattedContent << std::endl;

    // Case-insensitive replacement
    std::string caseInsensitiveText = "Hello WORLD, hello World, HELLO world!";
    std::regex casePattern(R"(hello)", std::regex_constants::icase);
    std::string caseReplaced = std::regex_replace(
        caseInsensitiveText, casePattern, "Hi"
    );

    std::cout << "\nCase-insensitive replacement:" << std::endl;
    std::cout << "Original: " << caseInsensitiveText << std::endl;
    std::cout << "Replaced: " << caseReplaced << std::endl;
}

// 5. Advanced pattern matching
void AdvancedPatternMatching() {
    std::cout << "\n=== Advanced Pattern Matching ===" << std::endl;

    // Match nested parentheses (simplified)
    std::string nestedText = "(a(b(c)d)e)f(g)h";
    std::regex nestedPattern(R"([^()]*\([^()]*\))*[^()]*)");

    std::cout << "Nested parentheses check:" << std::endl;
    std::cout << "String: " << nestedText << std::endl;
    std::cout << "Pattern matches: " << (std::regex_match(nestedText, nestedPattern) ? "Yes" : "No") << std::endl;

    // Find palindromes (simplified for demonstration)
    std::vector<std::string> words = {
        "level", "hello", "radar", "world", "madam", "c++", "refer"
    };

    std::cout << "\nPalindrome detection:" << std::endl;
    for (const auto& word : words) {
        bool isPalindrome = IsPalindrome(word);
        std::cout << word << " - " << (isPalindrome ? "Palindrome" : "Not palindrome") << std::endl;
    }

    // Extract quoted text
    std::string quotedText = R"("Hello" she said, "How are you?" "I'm fine" he replied.)";
    std::regex quotePattern(R"("([^"]*)")");

    std::vector<std::string> quotes;
    std::sregex_iterator quoteIter(quotedText.begin(), quotedText.end(), quotePattern);
    std::sregex_iterator quoteEnd;

    std::cout << "\nExtracted quotes:" << std::endl;
    for (; quoteIter != quoteEnd; ++quoteIter) {
        std::smatch match = *quoteIter;
        quotes.push_back(match[1].str()); // Group 1 contains content inside quotes
        std::cout << "  "" << match[1].str() << """ << std::endl;
    }

    // Find repeated patterns
    std::string repeatText = "abcabcabc xyzxyz abcabcabcabc";
    std::regex repeatPattern(R"((\w+)\1+)");

    std::cout << "\nRepeated patterns in: " << repeatText << std::endl;
    std::sregex_iterator repeatIter(repeatText.begin(), repeatText.end(), repeatPattern);
    std::sregex_iterator repeatEnd;

    for (; repeatIter != repeatEnd; ++repeatIter) {
        std::smatch match = *repeatIter;
        std::cout << "  Found repeat of: '" << match[1].str() << "' -> '" << match[0].str() << "'" << std::endl;
    }

    // Match balanced tags (XML/HTML like)
    std::string xmlText = "<div><p>Hello</p><span>World</span></div>";
    std::regex tagPattern(R"(<(\w+)>.*?</\2>)");

    std::cout << "\nXML-like tag matching:" << std::endl;
    std::cout << "String: " << xmlText << std::endl;
    std::cout << "Has balanced tags: " << (std::regex_match(xmlText, tagPattern) ? "Yes" : "No") << std::endl;
}

// Helper function to check palindrome (simplified)
bool IsPalindrome(const std::string& str) {
    std::string cleanStr;
    for (char c : str) {
        if (std::isalnum(c)) {
            cleanStr += std::tolower(c);
        }
    }
    return cleanStr == std::string(cleanStr.rbegin(), cleanStr.rend());
}

// 6. Performance comparison
void RegexPerformanceComparison() {
    std::cout << "\n=== Regex Performance Comparison ===" << std::endl;

    const int ITERATIONS = 10000;
    std::string testText = "This is a test string with multiple words and some numbers like 123 and 4567.";

    // Test different regex approaches
    std::vector<std::pair<std::string, std::regex>> patterns = {
        { "Simple word", std::regex(R"(\w+)") },
        { "Number pattern", std::regex(R"(\d+)") },
        { "Complex pattern", std::regex(R"([A-Z][a-z]+\s+[a-z]+)") },
        { "Email pattern", std::regex(R"([\w\.-]+@[\w\.-]+\.[a-zA-Z]{2,})") }
    };

    for (const auto& [name, pattern] : patterns) {
        auto start = std::chrono::high_resolution_clock::now();

        int matches = 0;
        for (int i = 0; i < ITERATIONS; i++) {
            std::sregex_iterator iter(testText.begin(), testText.end(), pattern);
            std::sregex_iterator end;
            for (; iter != end; ++iter) {
                matches++;
            }
        }

        auto end = std::chrono::high_resolution_clock::now();
        auto duration = std::chrono::duration_cast<std::chrono::microseconds>(end - start);

        std::cout << name << ": " << duration.count() << " μs ("
                  << matches << " matches found)" << std::endl;
    }

    // Compare regex_match vs regex_search vs regex_iterator
    std::regex simplePattern(R"([^\s]+)");
    std::string searchText = "one two three four five six seven eight nine ten";

    // Using regex_iterator (most flexible)
    auto start1 = std::chrono::high_resolution_clock::now();
    for (int i = 0; i < ITERATIONS; i++) {
        std::sregex_iterator iter(searchText.begin(), searchText.end(), simplePattern);
        std::sregex_iterator end;
        int count = 0;
        for (; iter != end; ++iter) {
            count++;
        }
    }
    auto end1 = std::chrono::high_resolution_clock::now();
    auto duration1 = std::chrono::duration_cast<std::chrono::microseconds>(end1 - start1);

    // Using manual search with regex_search
    auto start2 = std::chrono::high_resolution_clock::now();
    for (int i = 0; i < ITERATIONS; i++) {
        std::smatch match;
        std::string remaining = searchText;
        int count = 0;
        while (std::regex_search(remaining, match, simplePattern)) {
            count++;
            remaining = match.suffix();
        }
    }
    auto end2 = std::chrono::high_resolution_clock::now();
    auto duration2 = std::chrono::duration_cast<std::chrono::microseconds>(end2 - start2);

    std::cout << "\nMethod comparison for word extraction:" << std::endl;
    std::cout << "regex_iterator: " << duration1.count() << " μs" << std::endl;
    std::cout << "regex_search loop: " << duration2.count() << " μs" << std::endl;
}

// 7. Practical text processing examples
void PracticalTextProcessing() {
    std::cout << "\n=== Practical Text Processing Examples ===" << std::endl;

    // Log file parsing
    std::vector<std::string> logLines = {
        "2023-12-25 10:30:45 [INFO] Application started",
        "2023-12-25 10:31:02 [ERROR] Connection failed to database",
        "2023-12-25 10:31:15 [WARNING] Retrying connection",
        "2023-12-25 10:31:30 [INFO] Connection established",
        "2023-12-25 10:32:00 [DEBUG] Processing request #12345"
    };

    std::regex logPattern(R"((\d{4}-\d{2}-\d{2}\s+\d{2}:\d{2}:\d{2})\s+\[(\w+)\]\s+(.*))");

    std::map<std::string, std::vector<std::string>> logEntries;

    std::cout << "Parsing log file entries:" << std::endl;
    for (const auto& line : logLines) {
        std::smatch match;
        if (std::regex_match(line, match, logPattern)) {
            std::string timestamp = match[1].str();
            std::string level = match[2].str();
            std::string message = match[3].str();

            logEntries[level].push_back(message);
            std::cout << level << ": " << message << " (" << timestamp << ")" << std::endl;
        }
    }

    // Code comment extraction
    std::string codeWithComments = R"(
        // This is a single line comment
        int x = 5; /* This is a block comment */
        /*
         * Multi-line comment
         * spanning multiple lines
         */
        int y = 10; // Another comment
    )";

    std::regex commentPattern(R"((//.*?$|/\*.*?\*/))");
    std::vector<std::string> comments;

    std::sregex_iterator commentIter(codeWithComments.begin(), codeWithComments.end(),
                                   commentPattern, std::regex_constants::mod_s);
    std::sregex_iterator commentEnd;

    std::cout << "\nExtracted code comments:" << std::endl;
    for (; commentIter != commentEnd; ++commentIter) {
        std::string comment = commentIter->str();
        // Clean up multi-line comments
        comment = std::regex_replace(comment, std::regex(R"(\s*
\s*\*)"), " ");
        comment = std::regex_replace(comment, std::regex(R"(/\*|\*/)"), "");
        comment = std::regex_replace(comment, std::regex(R"(//\s*)"), "");
        // Trim whitespace
        comment.erase(0, comment.find_first_not_of(" \t"));
        comment.erase(comment.find_last_not_of(" \t") + 1);

        if (!comment.empty()) {
            comments.push_back(comment);
            std::cout << "  " << comment << std::endl;
        }
    }

    // Data cleaning
    std::string dirtyData = R"(
        John Doe,    25,   New York
        Jane Smith,30,Los Angeles
        Bob Johnson,  35 , Chicago
        Alice Williams,28,Boston
    )";

    std::cout << "\nData cleaning example:" << std::endl;
    std::cout << "Original: " << dirtyData << std::endl;

    // Clean and format data
    std::vector<std::string> cleanedLines;
    std::istringstream iss(dirtyData);
    std::string line;

    while (std::getline(iss, line)) {
        // Remove leading/trailing whitespace
        line = std::regex_replace(line, std::regex(R"(^\s+|\s+$)"), "");
        // Replace multiple spaces with single comma
        line = std::regex_replace(line, std::regex(R"(\s+,\s*|\s+,|,\s+)"), ", ");

        if (!line.empty()) {
            cleanedLines.push_back(line);
        }
    }

    std::cout << "Cleaned data:" << std::endl;
    for (const auto& cleanLine : cleanedLines) {
        std::cout << "  " << cleanLine << std::endl;
    }
}

int main() {
    std::cout << "=== C++ Windows String Processing - Regular Expressions ===" << std::endl;
    std::cout << "Demonstrating comprehensive regex pattern matching and text processing\n" << std::endl;

    try {
        // Run all regex examples
        BasicRegexOperations();
        PatternMatchingWithGroups();
        TextValidation();
        TextExtractionAndReplacement();
        AdvancedPatternMatching();
        RegexPerformanceComparison();
        PracticalTextProcessing();

        std::cout << "\nAll regex pattern matching examples completed successfully!" << std::endl;

    } catch (const std::exception& e) {
        std::cerr << "Unexpected error: " << e.what() << std::endl;
        return 1;
    }

    return 0;
}

#include <iostream>
#include <string>
#include <vector>
#include <map>
#include <regex>
#include <sstream>
#include <algorithm>
#include <cctype>
#include <unordered_map>
#include <chrono>

// 1. Basic string replacement
void BasicStringReplacement() {
    std::cout << "=== Basic String Replacement ===" << std::endl;

    std::string text = "The quick brown fox jumps over the lazy dog.";
    std::cout << "Original: " << text << std::endl;

    // Simple replacement
    std::string replaced1 = text;
    size_t pos = replaced1.find("fox");
    if (pos != std::string::npos) {
        replaced1.replace(pos, 3, "cat");
        std::cout << "Replace 'fox' with 'cat': " << replaced1 << std::endl;
    }

    // Replace all occurrences
    std::string replaced2 = text;
    std::string from = "the";
    std::string to = "a";

    size_t startPos = 0;
    while ((startPos = replaced2.find(from, startPos)) != std::string::npos) {
        replaced2.replace(startPos, from.length(), to);
        startPos += to.length(); // Move past the replacement
    }
    std::cout << "Replace all 'the' with 'a': " << replaced2 << std::endl;

    // Case-insensitive replacement (manual implementation)
    std::string replaced3 = text;
    std::string target = "THE";
    std::string replacement = "A";

    // Convert both to lowercase for comparison, but preserve original case in replacement
    std::string lowerText = replaced3;
    std::transform(lowerText.begin(), lowerText.end(), lowerText.begin(), ::tolower);

    size_t currentPos = 0;
    size_t originalPos = 0;

    while ((currentPos = lowerText.find(target, currentPos)) != std::string::npos) {
        size_t replaceStart = currentPos + (originalPos - lowerText.find(lowerText, originalPos));
        replaced3.replace(replaceStart, target.length(), replacement);
        lowerText.replace(currentPos, target.length(), replacement);
        currentPos += replacement.length();
        originalPos += replacement.length();
    }

    std::cout << "Case-insensitive 'the' -> 'A': " << replaced3 << std::endl;
}

// 2. Using regex for advanced replacement
void RegexReplacement() {
    std::cout << "\n=== Regex Replacement ===" << std::endl;

    std::string text = "Contact: john.doe@example.com, Phone: (555) 123-4567, Alt: (555) 987-6543";
    std::cout << "Original: " << text << std::endl;

    // Replace all email addresses with placeholder
    std::regex emailPattern(R"([\w\.-]+@[\w\.-]+\.[a-zA-Z]{2,})");
    std::string emailReplaced = std::regex_replace(text, emailPattern, "[EMAIL PROTECTED]");
    std::cout << "Emails replaced: " << emailReplaced << std::endl;

    // Replace phone numbers with standardized format
    std::regex phonePattern(R"(\(\d{3}\)\s*(\d{3})[-\s]?(\d{4}))");
    std::string phoneReplaced = std::regex_replace(text, phonePattern, "$1$2$3");
    std::cout << "Phone numbers standardized: " << phoneReplaced << std::endl;

    // Multiple replacements in sequence
    std::string multiText = "Price: $19.99, Discount: 15%, Tax: 8.5%, Total: $22.90";
    std::cout << "\nOriginal pricing: " << multiText << std::endl;

    // Remove currency symbols
    std::string noCurrency = std::regex_replace(multiText, std::regex(R"(\$)"), "");
    std::cout << "Currency removed: " << noCurrency << std::endl;

    // Format percentages consistently
    std::regex percentPattern(R"(\b(\d+(?:\.\d+)?)%\b)");
    std::string formattedPercents = std::regex_replace(noCurrency, percentPattern, "$1 percent");
    std::cout << "Formatted percentages: " << formattedPercents << std::endl;

    // Extract and format numbers
    std::regex numberPattern(R"(\b(\d+(?:\.\d+)?)\b)");
    std::string formattedNumbers = std::regex_replace(formattedPercents, numberPattern, "$1.00");
    std::cout << "Numbers with .00: " << formattedNumbers << std::endl;
}

// 3. Conditional replacement
void ConditionalReplacement() {
    std::cout << "\n=== Conditional Replacement ===" << std::endl;

    std::vector<std::string> words = {"cat", "dog", "mouse", "elephant", "ant", "giraffe"};
    std::cout << "Original words: ";
    for (const auto& word : words) {
        std::cout << word << " ";
    }
    std::cout << std::endl;

    // Replace based on word length
    std::vector<std::string> lengthReplaced;
    for (const auto& word : words) {
        if (word.length() <= 3) {
            lengthReplaced.push_back("SMALL");
        } else if (word.length() <= 5) {
            lengthReplaced.push_back("MEDIUM");
        } else {
            lengthReplaced.push_back("LARGE");
        }
    }

    std::cout << "Length-based replacement: ";
    for (const auto& word : lengthReplaced) {
        std::cout << word << " ";
    }
    std::cout << std::endl;

    // Replace based on starting letter
    std::vector<std::string> letterReplaced;
    for (const auto& word : words) {
        if (!word.empty()) {
            char first = tolower(word[0]);
            if (first >= 'a' && first <= 'm') {
                letterReplaced.push_back("FIRST_HALF");
            } else {
                letterReplaced.push_back("SECOND_HALF");
            }
        }
    }

    std::cout << "Alphabet-based replacement: ";
    for (const auto& word : letterReplaced) {
        std::cout << word << " ";
    }
    std::cout << std::endl;

    // Replace words containing specific patterns
    std::string text = "The bakery sells bread, cakes, and cookies. The bread is fresh.";
    std::cout << "\nOriginal: " << text << std::endl;

    // Words containing 'bread' -> replace with '[BAKERY ITEM]'
    std::vector<std::string> wordsInText = SplitWords(text);
    for (auto& word : wordsInText) {
        if (word.find("bread") != std::string::npos) {
            word = "[BAKERY ITEM]";
        }
    }
    std::string conditionalText = JoinWords(wordsInText);
    std::cout << "Conditional replacement: " << conditionalText << std::endl;
}

// Helper function to split text into words
std::vector<std::string> SplitWords(const std::string& text) {
    std::vector<std::string> words;
    std::istringstream iss(text);
    std::string word;
    while (iss >> word) {
        // Remove punctuation
        word.erase(std::remove_if(word.begin(), word.end(), ::ispunct), word.end());
        if (!word.empty()) {
            words.push_back(word);
        }
    }
    return words;
}

// Helper function to join words
std::string JoinWords(const std::vector<std::string>& words) {
    std::string result;
    for (size_t i = 0; i < words.size(); i++) {
        result += words[i];
        if (i < words.size() - 1) {
            result += " ";
        }
    }
    return result;
}

// 4. Multiple simultaneous replacements
void MultipleReplacements() {
    std::cout << "\n=== Multiple Simultaneous Replacements ===" << std::endl;

    std::string text = "Hello World! How are you today? I hope you're doing well. Have a great day!";
    std::cout << "Original: " << text << std::endl;

    // Define replacement map
    std::unordered_map<std::string, std::string> replacements = {
        {"Hello", "Hi"},
        {"World", "Everyone"},
        {"great", "wonderful"},
        {"well", "fine"},
        {"hope", "wish"}
    };

    // Apply all replacements
    std::string multiReplaced = ApplyMultipleReplacements(text, replacements);
    std::cout << "Multiple replacements: " << multiReplaced << std::endl;

    // Case-insensitive multiple replacements
    std::unordered_map<std::string, std::string> caseInsensitiveReplacements = {
        {"HELLO", "Hi"},
        {"world", "Everyone"},
        {"YOU", "you"},
        {"today", "now"},
        {"DAY", "evening"}
    };

    std::string caseInsensitiveResult = ApplyCaseInsensitiveReplacements(text, caseInsensitiveReplacements);
    std::cout << "Case-insensitive replacements: " << caseInsensitiveResult << std::endl;

    // Pattern-based replacements
    std::unordered_map<std::string, std::string> patternReplacements = {
        {R"(\b\w{4}\b)", "FOUR"},      // 4-letter words
        {R"(\b\w+\!)"), "EXCLAMATED!"}, // Words ending with !
        {R"([?])"}, "?"}                // Just question marks (no change, demonstration)
    };

    std::string patternResult = ApplyPatternReplacements(text, patternReplacements);
    std::cout << "Pattern-based replacements: " << patternResult << std::endl;
}

// Apply multiple word replacements
std::string ApplyMultipleReplacements(const std::string& text,
                                      const std::unordered_map<std::string, std::string>& replacements) {
    std::string result = text;

    for (const auto& [from, to] : replacements) {
        size_t pos = 0;
        while ((pos = result.find(from, pos)) != std::string::npos) {
            result.replace(pos, from.length(), to);
            pos += to.length();
        }
    }

    return result;
}

// Apply case-insensitive replacements
std::string ApplyCaseInsensitiveReplacements(const std::string& text,
                                           const std::unordered_map<std::string, std::string>& replacements) {
    std::string result = text;

    for (const auto& [from, to] : replacements) {
        // Convert both to lowercase for comparison
        std::string lowerResult = result;
        std::string lowerFrom = from;
        std::transform(lowerResult.begin(), lowerResult.end(), lowerResult.begin(), ::tolower);
        std::transform(lowerFrom.begin(), lowerFrom.end(), lowerFrom.begin(), ::tolower);

        size_t pos = 0;
        while ((pos = lowerResult.find(lowerFrom, pos)) != std::string::npos) {
            result.replace(pos, from.length(), to);
            lowerResult.replace(pos, from.length(), to);
            pos += to.length();
        }
    }

    return result;
}

// Apply regex pattern replacements
std::string ApplyPatternReplacements(const std::string& text,
                                     const std::unordered_map<std::string, std::string>& replacements) {
    std::string result = text;

    for (const auto& [pattern, replacement] : replacements) {
        try {
            std::regex regex(pattern);
            result = std::regex_replace(result, regex, replacement);
        } catch (const std::regex_error& e) {
            std::cout << "Invalid regex pattern '" << pattern << "': " << e.what() << std::endl;
        }
    }

    return result;
}

// 5. Text transformation pipelines
void TransformationPipelines() {
    std::cout << "\n=== Text Transformation Pipelines ===" << std::endl;

    std::string rawText = R"(
        THE QUICK BROWN FOX JUMPS OVER THE LAZY DOG!!!
        This is a test... With punctuation??? And numbers 12345.
        Email: user@domain.com, Phone: (555) 123-4567
    )";

    std::cout << "Original text:" << std::endl;
    std::cout << rawText << std::endl;

    // Pipeline 1: Normalization
    std::string normalized = TextNormalizationPipeline(rawText);
    std::cout << "\n=== Normalization Pipeline ===" << std::endl;
    std::cout << normalized << std::endl;

    // Pipeline 2: Data extraction
    std::string extracted = DataExtractionPipeline(rawText);
    std::cout << "\n=== Data Extraction Pipeline ===" << std::endl;
    std::cout << extracted << std::endl;

    // Pipeline 3: Anonymization
    std::string anonymized = AnonymizationPipeline(rawText);
    std::cout << "\n=== Anonymization Pipeline ===" << std::endl;
    std::cout << anonymized << std::endl;

    // Pipeline 4: Formatting
    std::string formatted = FormattingPipeline(rawText);
    std::cout << "\n=== Formatting Pipeline ===" << std::endl;
    std::cout << formatted << std::endl;
}

// Pipeline 1: Text normalization
std::string TextNormalizationPipeline(const std::string& text) {
    std::string result = text;

    // Step 1: Convert to lowercase
    std::transform(result.begin(), result.end(), result.begin(), ::tolower);

    // Step 2: Remove extra whitespace
    result = std::regex_replace(result, std::regex(R"(\s+)"), " ");

    // Step 3: Remove punctuation
    result = std::regex_replace(result, std::regex(R"([^a-z0-9\s])"), "");

    // Step 4: Trim leading/trailing whitespace
    result.erase(0, result.find_first_not_of(" \t\n\r"));
    result.erase(result.find_last_not_of(" \t\n\r") + 1);

    return result;
}

// Pipeline 2: Data extraction
std::string DataExtractionPipeline(const std::string& text) {
    std::string result = text;

    // Step 1: Extract emails and mark them
    std::regex emailPattern(R"([\w\.-]+@[\w\.-]+\.[a-zA-Z]{2,})");
    result = std::regex_replace(result, emailPattern, "[EMAIL:$&]");

    // Step 2: Extract phone numbers and mark them
    std::regex phonePattern(R"(\(\d{3}\)\s*\d{3}[-\s]?\d{4})");
    result = std::regex_replace(result, phonePattern, "[PHONE:$&]");

    // Step 3: Extract numbers and mark them
    std::regex numberPattern(R"(\b\d+\b)");
    result = std::regex_replace(result, numberPattern, "[NUM:$&]");

    // Step 4: Convert to uppercase for visibility
    std::transform(result.begin(), result.end(), result.begin(), ::toupper);

    return result;
}

// Pipeline 3: Anonymization
std::string AnonymizationPipeline(const std::string& text) {
    std::string result = text;

    // Step 1: Replace emails with generic placeholder
    std::regex emailPattern(R"([\w\.-]+@[\w\.-]+\.[a-zA-Z]{2,})");
    result = std::regex_replace(result, emailPattern, "user@domain.com");

    // Step 2: Replace phone numbers
    std::regex phonePattern(R"(\(\d{3}\)\s*\d{3}[-\s]?\d{4})");
    result = std::regex_replace(result, phonePattern, "(XXX) XXX-XXXX");

    // Step 3: Replace proper nouns (simplified - capitalize words)
    std::regex wordPattern(R"(\b[A-Z][a-z]+\b)");
    result = std::regex_replace(result, wordPattern, "[PROPER_NOUN]");

    // Step 4: Replace numbers with ranges
    std::regex numberPattern(R"(\b\d+\b)");
    result = std::regex_replace(result, numberPattern, "[NUMBER]");

    return result;
}

// Pipeline 4: Text formatting
std::string FormattingPipeline(const std::string& text) {
    std::string result = text;

    // Step 1: Add paragraph breaks
    result = std::regex_replace(result, std::regex(R"(\s*\n\s*)"), "

");

    // Step 2: Capitalize sentences
    std::regex sentencePattern(R"([.!?]\s*([a-z]))");
    result = std::regex_replace(result, sentencePattern, [](const std::smatch& m) {
        return m[0].str().substr(0, m[0].str().length() - 1) +
               std::string(1, std::toupper(m[1].str()[0]));
    });

    // Step 3: Ensure proper spacing around punctuation
    result = std::regex_replace(result, std::regex(R"(\s*([,.!?])\s*)"), "$1 ");
    result = std::regex_replace(result, std::regex(R"(\s+([,.!?])\s+)"), "$1 ");
    result = std::regex_replace(result, std::regex(R"(\s+$)"), "");

    // Step 4: Ensure first letter is capitalized
    if (!result.empty() && std::islower(result[0])) {
        result[0] = std::toupper(result[0]);
    }

    return result;
}

// 6. Performance-optimized bulk replacement
void PerformanceOptimizedReplacement() {
    std::cout << "\n=== Performance-Optimized Bulk Replacement ===" << std::endl;

    // Generate large test data
    const int SIZE = 10000;
    std::string testData;
    testData.reserve(SIZE * 20); // Pre-allocate

    std::vector<std::string> words = {"apple", "banana", "cherry", "date", "elderberry"};
    for (int i = 0; i < SIZE; i++) {
        testData += words[i % words.size()] + " ";
    }
    testData += "END";

    std::cout << "Generated test data with " << testData.length() << " characters" << std::endl;

    // Replacement map
    std::unordered_map<std::string, std::string> replacements = {
        {"apple", "FRUIT"},
        {"banana", "TROPICAL"},
        {"cherry", "BERRY"},
        {"date", "PALM"},
        {"elderberry", "ANTIOXIDANT"}
    };

    // Method 1: Sequential find/replace
    auto start1 = std::chrono::high_resolution_clock::now();
    std::string result1 = testData;
    for (const auto& [from, to] : replacements) {
        size_t pos = 0;
        while ((pos = result1.find(from, pos)) != std::string::npos) {
            result1.replace(pos, from.length(), to);
            pos += to.length();
        }
    }
    auto end1 = std::chrono::high_resolution_clock::now();
    auto duration1 = std::chrono::duration_cast<std::chrono::milliseconds>(end1 - start1);

    // Method 2: Build new string (more efficient for many replacements)
    auto start2 = std::chrono::high_resolution_clock::now();
    std::string result2;
    result2.reserve(testData.length() * 2); // Pre-allocate

    std::string current;
    for (char c : testData) {
        current += c;

        // Check if current token matches any replacement
        auto it = replacements.find(current);
        if (it != replacements.end()) {
            result2 += it->second;
            current.clear();
        } else if (c == ' ' || c == '\t' || c == '\n') {
            result2 += current;
            result2 += c;
            current.clear();
        }
    }
    result2 += current; // Add remaining characters

    auto end2 = std::chrono::high_resolution_clock::now();
    auto duration2 = std::chrono::duration_cast<std::chrono::milliseconds>(end2 - start2);

    // Method 3: Using regex (usually slower but more flexible)
    auto start3 = std::chrono::high_resolution_clock::now();
    std::string result3 = testData;
    for (const auto& [from, to] : replacements) {
        std::regex pattern("\b" + from + "\b");
        result3 = std::regex_replace(result3, pattern, to);
    }
    auto end3 = std::chrono::high_resolution_clock::now();
    auto duration3 = std::chrono::duration_cast<std::chrono::milliseconds>(end3 - start3);

    std::cout << "Performance comparison:" << std::endl;
    std::cout << "Sequential find/replace: " << duration1.count() << " ms" << std::endl;
    std::cout << "Build new string: " << duration2.count() << " ms" << std::endl;
    std::cout << "Regex replacement: " << duration3.count() << " ms" << std::endl;

    // Verify all methods produce same result
    bool sameResult = (result1 == result2) && (result2 == result3);
    std::cout << "All methods produce same result: " << (sameResult ? "Yes" : "No") << std::endl;
}

// 7. Advanced replacement scenarios
void AdvancedReplacementScenarios() {
    std::cout << "\n=== Advanced Replacement Scenarios ===" << std::endl;

    // Scenario 1: Template variable replacement
    std::string templateStr = "Hello {name}, your order #{order} is {status}. Total: ${amount}.";
    std::map<std::string, std::string> variables = {
        {"{name}", "John Doe"},
        {"{order}", "12345"},
        {"{status}", "shipped"},
        {"{amount}", "99.99"}
    };

    std::string filledTemplate = FillTemplate(templateStr, variables);
    std::cout << "Template filling:" << std::endl;
    std::cout << "Template: " << templateStr << std::endl;
    std::cout << "Filled:   " << filledTemplate << std::endl;

    // Scenario 2: Smart quote replacement
    std::string quotes = "This is 'a test' with "smart quotes" and 'single quotes'.";
    std::string smartQuotes = ReplaceWithSmartQuotes(quotes);
    std::cout << "\nSmart quote replacement:" << std::endl;
    std::cout << "Original: " << quotes << std::endl;
    std::cout << "Smart:    " << smartQuotes << std::endl;

    // Scenario 3: URL encoding/decoding replacement
    std::string url = "https://example.com/search?q=hello world&category=C++ Programming";
    std::string encoded = EncodeUrl(url);
    std::string decoded = DecodeUrl(encoded);
    std::cout << "\nURL encoding/decoding:" << std::endl;
    std::cout << "Original: " << url << std::endl;
    std::cout << "Encoded:  " << encoded << std::endl;
    std::cout << "Decoded:  " << decoded << std::endl;

    // Scenario 4: Number formatting replacement
    std::string numbers = "Values: 1234, 56.789, 0.42, 1000.00";
    std::string formattedNumbers = FormatNumbers(numbers);
    std::cout << "\nNumber formatting:" << std::endl;
    std::cout << "Original: " << numbers << std::endl;
    std::cout << "Formatted: " << formattedNumbers << std::endl;

    // Scenario 5: HTML entity replacement
    std::string html = "5 < 10 && a > b. Use &lt; and &gt; in HTML.";
    std::string htmlEntities = ProcessHtmlEntities(html);
    std::cout << "\nHTML entity processing:" << std::endl;
    std::cout << "Original: " << html << std::endl;
    std::cout << "Processed: " << htmlEntities << std::endl;
}

// Fill template with variables
std::string FillTemplate(const std::string& templateStr, const std::map<std::string, std::string>& variables) {
    std::string result = templateStr;

    for (const auto& [placeholder, value] : variables) {
        size_t pos = 0;
        while ((pos = result.find(placeholder, pos)) != std::string::npos) {
            result.replace(pos, placeholder.length(), value);
            pos += value.length();
        }
    }

    return result;
}

// Replace straight quotes with smart quotes
std::string ReplaceWithSmartQuotes(const std::string& text) {
    std::string result = text;
    bool inSingleQuote = false;
    bool inDoubleQuote = false;

    for (size_t i = 0; i < result.length(); i++) {
        if (result[i] == '\''' && !inDoubleQuote && (i == 0 || result[i-1] != '\\')) {
            result[i] = inSingleQuote ? ''' : '"';
            inSingleQuote = !inSingleQuote;
        } else if (result[i] == '"' && !inSingleQuote) {
            result[i] = inDoubleQuote ? '"' : '"';
            inDoubleQuote = !inDoubleQuote;
        }
    }

    return result;
}

// Simple URL encoding (basic implementation)
std::string EncodeUrl(const std::string& url) {
    std::string encoded;
    for (char c : url) {
        if (std::isalnum(c) || c == '-' || c == '_' || c == '.' || c == '~') {
            encoded += c;
        } else if (c == ' ') {
            encoded += "%20";
        } else {
            std::ostringstream oss;
            oss << std::hex << std::uppercase << static_cast<int>(static_cast<unsigned char>(c));
            encoded += "%" + oss.str();
        }
    }
    return encoded;
}

// Simple URL decoding
std::string DecodeUrl(const std::string& encoded) {
    std::string decoded;
    for (size_t i = 0; i < encoded.length(); i++) {
        if (encoded[i] == '%' && i + 2 < encoded.length()) {
            std::string hexStr = encoded.substr(i + 1, 2);
            char c = static_cast<char>(std::stoi(hexStr, nullptr, 16));
            decoded += c;
            i += 2;
        } else if (encoded[i] == '+') {
            decoded += ' ';
        } else {
            decoded += encoded[i];
        }
    }
    return decoded;
}

// Format numbers with thousands separators
std::string FormatNumbers(const std::string& text) {
    std::string result = text;
    std::regex numberPattern(R"(\b\d+(?:\.\d+)?\b)");

    result = std::regex_replace(result, numberPattern, [](const std::smatch& match) {
        std::string numStr = match.str();
        size_t dotPos = numStr.find('.');

        std::string integerPart = (dotPos != std::string::npos) ? numStr.substr(0, dotPos) : numStr;
        std::string decimalPart = (dotPos != std::string::npos) ? numStr.substr(dotPos) : "";

        // Add thousands separators to integer part
        std::string formattedInt;
        int count = 0;
        for (int i = integerPart.length() - 1; i >= 0; i--) {
            if (count > 0 && count % 3 == 0) {
                formattedInt = "," + formattedInt;
            }
            formattedInt = integerPart[i] + formattedInt;
            count++;
        }

        return formattedInt + decimalPart;
    });

    return result;
}

// Process HTML entities
std::string ProcessHtmlEntities(const std::string& html) {
    std::string result = html;

    // Define common HTML entities
    std::unordered_map<std::string, std::string> entities = {
        {"&lt;", "<"},
        {"&gt;", ">"},
        {"&amp;", "&"},
        {"&quot;", """},
        {"&apos;", "'"}
    };

    for (const auto& [entity, character] : entities) {
        size_t pos = 0;
        while ((pos = result.find(entity, pos)) != std::string::npos) {
            result.replace(pos, entity.length(), character);
            pos += character.length();
        }
    }

    return result;
}

int main() {
    std::cout << "=== C++ Windows String Processing - String Replacement ===" << std::endl;
    std::cout << "Demonstrating comprehensive string replacement and transformation techniques\n" << std::endl;

    try {
        // Run all replacement examples
        BasicStringReplacement();
        RegexReplacement();
        ConditionalReplacement();
        MultipleReplacements();
        TransformationPipelines();
        PerformanceOptimizedReplacement();
        AdvancedReplacementScenarios();

        std::cout << "\nAll string replacement examples completed successfully!" << std::endl;

    } catch (const std::exception& e) {
        std::cerr << "Unexpected error: " << e.what() << std::endl;
        return 1;
    }

    return 0;
}