Convert std::string to C-style String

Converting a std::string to a char* is a common operation in C++ programming, especially when dealing with functions or APIs that require C-style strings. While std::string provides powerful string manipulation capabilities, sometimes you may need to convert it to a C-style string for compatibility reasons. This tutorial explains how to convert std::string to C-style string.

const char*

Use c_str function to convert std::string to const char*. The returned pointer points to a constant array of characters, and you are not allowed to modify the content of the string through this pointer.

#include <iostream>

int main()
{
    std::string str = "Hello world";
    const char *cstr = str.c_str();

    std::cout << cstr << std::endl;

    return 0;
}

char*

Use data function to convert std::string to char*. It provides a non-constant pointer, allowing you to modify the content of the string through this pointer.

#include <iostream>

int main()
{
    std::string str = "Hello world";
    char *cstr = str.data();

    std::cout << cstr << std::endl;

    return 0;
}

Both c_str and data functions ensure that the returned pointer points to a null-terminated sequence of characters, making it suitable for use with functions expecting C-style strings.