Facebook Page Twitter Page LinkedIn Page
× C++ Standard Library C++ STL Library

The C++ string::swap function is used to exchange the content of one string with the content of another string. Please note that the size of two strings may differ.


void swap (string& lhs, string& rhs);
void swap (string& lhs, string& rhs);


lhs First string.
rhs Second string.

Return Value


Time Complexity

Constant i.e, Θ(1).


In the below example, the string::swap function is used to exchange the content of string MyStr1 with the content of string MyStr2.

#include <iostream>
#include <string>
using namespace std;
int main (){
  string MyStr1{"Hello"};
  string MyStr2{"World"};

  cout<<"Before Swapping, The MyStr1 contains:"<<MyStr1<<"\n";
  cout<<"Before Swapping, The MyStr2 contains:"<<MyStr2<<"\n\n";

  swap(MyStr1, MyStr2);

  cout<<"After Swapping, The MyStr1 contains:"<<MyStr1<<"\n";
  cout<<"After Swapping, The MyStr2 contains:"<<MyStr2<<"\n";

  return 0;

The output of the above code will be:

Before Swapping, The MyStr1 contains:Hello
Before Swapping, The MyStr2 contains:World

After Swapping, The MyStr1 contains:World
After Swapping, The MyStr2 contains:Hello

❮ C++ - String Functions