basic_string c_str function in C++ STL

The basic_string::c_str() is a builtin function in C++ which returns a pointer to an array that contains a null-terminated sequence of characters representing the current value of the basic_string object. This array includes the same sequence of characters that make up the value of the basic_string object plus an additional terminating null-character at the end.

Syntax:

const CharT* c_str() const

Parameter: The function does not accept any parameter.

Return Value : The function returns a constant Null terminated pointer to the character array storage of the string.

Below is the implementation of the above function:

Program 1:

// C++ code for illustration of
// basic_string::c_str function
#include <bits/stdc++.h>
#include <string>
using namespace std;

int main()
{
    // declare a example string
    string s1 = "GeeksForGeeks";

    // check if the size of the string is same as the
    // size of character pointer given by c_str
    if (s1.size() == strlen(s1.c_str())) {
        cout << "s1.size is equal to strlen(s1.c_str()) " << endl;
    }
    else {
        cout << "s1.size is not equal to strlen(s1.c_str())" << endl;
    }

    // print the string
    printf("%s \n", s1.c_str());
}

Output:

s1.size is equal to strlen(s1.c_str()) 
GeeksForGeeks 

Program 2:

// C++ code for illustration of
// basic_string::c_str function
#include <bits/stdc++.h>
#include <string>
using namespace std;

int main()
{
    // declare a example string
    string s1 = "Aditya";

    // print the characters of the string
    for (int i = 0; i < s1.length(); i++) {
        cout << "The " << i + 1 << "th character of string " << s1
             << " is " << s1.c_str()[i] << endl;
    }
}

Output:

The 1th character of string Aditya is A
The 2th character of string Aditya is d
The 3th character of string Aditya is i
The 4th character of string Aditya is t
The 5th character of string Aditya is y
The 6th character of string Aditya is a