C++ Algorithm Functions swap()

C++ Algorithm swap() function swaps or say interchanges the values of two containers under reference.

Syntax

Parameter

a: It is the first container with some value.

b: It is another container with some value.

Return value

The function only swaps the values of two containers and does not return something.

Example 1

#include <iostream> 
#include <algorithm>
#include <vector>   
int main () 
{
  int a=14, b=9;
  std::swap(a,b);
  std::vector<int> sg (4,a), ss (6,b);      
  std::swap(sg,ss);                          
  std::cout << "sg contains:";
  for (std::vector<int>::iterator ti=sg.begin(); ti!=sg.end(); ti++)
    std::cout << ' ' << *ti;
  std::cout << '\n';

  return 0;
}

Output:

sg contains: 14 14 14 14 14 14

Example 2

#include <bits/stdc++.h>
using namespace std;
int main()
{
	int ss = 9;
	int sg = 14;
	cout << "Value of ss before swapping: " << ss << endl;
	cout << "Value of sg before swapping: " << sg << endl;
	swap(ss, sg);
	cout << "Value of ss after swapping: " << ss << endl;
	cout << "Value of sg after swapping: " << sg << endl;
	return 0;
}

Output:

Value of ss before swapping: 9
Value of sg before swapping: 14
Value of ss after swapping: 14
Value of sg after swapping: 9

Complexity

For arrays the function has N complexity as the operation of swapping is individually performed on each element. For non array the function has constant complexity.