Convert string to const char* in C++

In this article, we will discuss different ways to convert a string to const char* in C++.

Table Of Contents

Method 1: Using string::c_str() function

In C++, the string class provides a member function c_str(). It returns a const char pointer to the null terminated contents of the string. We can call this function to get a const char* to the characters in the string. Let’s see an example,

#include <iostream>
#include <string>

int main()
{
    std::string sampleText = "This is a sample text";

    // Convert string to const char*
    const char* textPtr = sampleText.c_str();

    std::cout << textPtr << std::endl;

    return 0;
}

Output:

This is a sample text

It converted a string to a const char pointer in C++.

Method 2: Using string::data() function

In C++, the string class provides a member function data(). It returns a const pointer, pointing to the internal contents os string. So, we can use this to get a const char* to the characters in the string. Let’s see an example,

#include <iostream>
#include <string>

int main()
{
    std::string sampleText = "This is a sample text";

    // Convert string to const char*
    const char* textPtr = sampleText.data();

    std::cout << textPtr << std::endl;

    return 0;
}

Output:

This is a sample text

It converted a string to a const char pointer in C++.

Method 3: Using [] operator

If you are using the latest compiler of C++ i.e. C++11 onwards, then you can directly take the address of first character of string i.e. &strObj[0]. As, from C++11 onwards,
std::string does the contiguous memory allocation for characters. So, we can just fetch the address of first character, and assign it to a const char pointer. Let’s see an example,

#include <iostream>
#include <string>

int main()
{
    std::string sampleText = "This is a sample text";

    // Convert string to const char*
    const char* textPtr = &sampleText[0];

    std::cout << textPtr << std::endl;

    return 0;
}

Output:

This is a sample text

It converted a string to a const char pointer in C++.

Summary

We learned about three different ways to convert a string into const char* in C++. Thanks.