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Convert numeric to string using string::to_string() in C++ STL

C++ STL: string::to_string() function with Example: In this tutorial, we will learn to convert numeric values to the string using to_string() function.
Submitted by IncludeHelp, on July 02, 2018

C++ STL - string::to_string() Function

to_string() is a library function of <string> header, it is used to convert numeric value (number) to string.

Syntax

string to_string(numberic_value);

Parameter(s)

• string is the return type i.e. function returns an string object that contains the numeric value in string format.
• numbric_value is the number which can be integer, float, long, double.

Example to convert numeric to string using string::to_string()

#include <iostream>
#include <string>
using namespace std;

int main() {
  // definition of different types of data type
  int intVal = 12345;
  float floatVal = 123.45f;
  long longVal = 123456789;

  // converting values to string an printing
  cout << "intVal (string format) : " << to_string(intVal) << endl;
  cout << "floatVal (string format) : " << to_string(floatVal) << endl;
  cout << "floatVal (string format) : " << to_string(longVal) << endl;

  return 0;
}

Output

intVal (string format) : 12345
floatVal (string format) : 123.449997
floatVal (string format) : 123456789

Converting expressions to string

Expressions results can also be converted to string directly (as the type of expression’s result is numeric)

Example

#include <iostream>
#include <string>
using namespace std;

int main() {
  cout << to_string(10 + 20 + 30 + 40) << endl;
  cout << to_string(10 + 20 + 12.34) << endl;
  cout << to_string(10 / 20 + 30 * 2) << endl;

  return 0;
}

Output

100
42.340000
60

Functions and object without using 'using namespace std'

using namespace std is an statement that tells to the compiler to use namespace named std, if we do not write this statement, then we need to use std:: with all functions, objects.

Example

#include <iostream>
#include <string>

int main() {
  std::cout << std::to_string(10 + 20 + 30 + 40) << std::endl;
  std::cout << std::to_string(10 + 20 + 12.34) << std::endl;
  std::cout << std::to_string(10 / 20 + 30 * 2) << std::endl;

  return 0;
}

Output

100
42.340000
60