int to string in C++

Written by

Garvit Gulati

Many times we need to convert an int value to a string for a number of purposes. To do this, we may use any of the following methods:

  1. Using string stream
  2. Using to_string() function

# Using string stream

String streams are similar to iostream and fstream but they allow us to perform I/O operations on string. Just like fstream, it has three main classes:

  1. stringstream: for both input and output
  2. ostringstream: for only output
  3. istringstream: for only input

To convert an int to a string using stringstream, we first create an output stream object which inserts a number as a stream into the object and then, with the help of str() function of stringstream, the number is internally converted to a string.

Implementation

#include <iostream>
#include <sstream>	//for string stream
#include <string>	//for strings
using namespace std;

int main()

{ int num = 10;

ostringstream ob;

ob &lt;&lt; num;	//pushing num into output string stream

string str;

str = ob.str();	//conversion of num to string

cout &lt;&lt; "String is:" &lt;&lt; str;

return 0;

}

Output

String is:10

 

# Using to_string() function

The C++ string header file provides a function to convert an int to string called to_string(). The function accepts a number of any datatype, int, float, long, double etc, and returns the number in the string.

Implementation:

#include <iostream>
#include <string>   	//for strings
using namespace std;

int main()

{ int num = 12;

string str;

str = to_string(num);

cout &lt;&lt; "String is:" &lt;&lt; str;

return 0;

}

Output

String is:12