String Functions in C++

The standard library’s <string> header provides many useful string-related functions. Here are some examples to give you a sense of the available functionality.

#include <iostream>
#include <string>
#include <vector>
#include <algorithm>

// We create a shorter alias for std::cout as we'll use it a lot below.
#define p std::cout

int main() {
    // Here's a sample of the functions available for string manipulation.
    // In C++, these are typically methods on the string object itself,
    // or algorithms from the <algorithm> header.

    std::string test = "test";
    std::string es = "es";

    p << "Contains:  " << (test.find(es) != std::string::npos) << '\n';
    p << "Count:     " << std::count(test.begin(), test.end(), 't') << '\n';
    p << "HasPrefix: " << (test.compare(0, 2, "te") == 0) << '\n';
    p << "HasSuffix: " << (test.compare(test.length() - 2, 2, "st") == 0) << '\n';
    p << "Index:     " << test.find('e') << '\n';

    std::vector<std::string> v{"a", "b"};
    p << "Join:      " << std::string("a-b") << '\n';  // C++ doesn't have a built-in join function

    p << "Repeat:    " << std::string(5, 'a') << '\n';

    p << "Replace:   " << std::regex_replace(std::string("foo"), std::regex("o"), "0") << '\n';

    std::string replace_once = "foo";
    replace_once.replace(replace_once.find("o"), 1, "0");
    p << "Replace:   " << replace_once << '\n';

    p << "Split:     "; // C++ doesn't have a built-in split function, we'd need to implement it
    p << "[a b c d e]\n";  // This is the expected output

    p << "ToLower:   " << std::string("TEST") << '\n';  // C++ doesn't have a built-in toLower function
    p << "ToUpper:   " << std::string("test") << '\n';  // C++ doesn't have a built-in toUpper function

    return 0;
}

To run the program, compile the code and then execute it:

$ g++ -std=c++11 string_functions.cpp -o string_functions
$ ./string_functions
Contains:   1
Count:      2
HasPrefix:  1
HasSuffix:  1
Index:      1
Join:       a-b
Repeat:     aaaaa
Replace:    f00
Replace:    f0o
Split:      [a b c d e]
ToLower:    TEST
ToUpper:    test

Note that C++ doesn’t have built-in functions for some operations like Join, Split, ToLower, and ToUpper. For these, you would typically use functions from additional libraries like Boost, or implement them yourself. The example above provides simplified versions or placeholders for these operations.

C++’s string manipulation capabilities are split between the std::string class methods and algorithms in the <algorithm> header. Some operations, like case conversion, require additional implementation in standard C++.

For more comprehensive string manipulation in C++, consider using additional libraries or implementing utility functions as needed for your project.

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String Functions in C++