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# swap

Exchanges the values of the elements between two types of objects

## Definition

The swap() algorithm is defined in the standard header <algorithm> and in the nonstandard backward-compatibility header <algo.h>.

## Interface

```#include <algorithm>
template <class Type>
void swap(
Type& left,
Type& right
);```

Parameters:
Parameter Description
left The first object to have its elements exchanged
right The second object to have its elements exchanged

## Description

Swap assigns the contents of `left` to `right` and the contents of `right` to `left`.

None.

## Complexity

Swap algorithm has a constant complexity. It performs one copy construction and two assignments.

Example:

##### Example - swap algorithm
Problem
This program illustrates the functionality of swap algorithm.
Workings
```#include <vector>
#include <algorithm>
#include <iostream>

using namespace std;

bool greaterthan(int value)
{  return value > 5;
}

int main()
{
vector <int> vec1, vec2;
vector <int>::iterator Iter1, Iter2, result;
int i;
for (i = 10; i<= 20; i++)
vec1.push_back(i);
int j;
for(j = 10; j <= 15; j++)
vec2.push_back(j);
cout<<"Vector vec1 data is:\n";
for(Iter1 = vec1.begin(); Iter1 != vec1.end(); Iter1++)
cout <<*Iter1<<" ";
cout <<endl;
cout <<"\nVector vec2 data is:\n";
for (Iter2 = vec2.begin(); Iter2 != vec2.end(); Iter2++)
cout<<*Iter2<<" ";
cout <<endl;
swap(vec1, vec2);
cout <<"\nNow, vector vec1 data is:\n";
for(Iter1 = vec1.begin(); Iter1 != vec1.end(); Iter1++)
cout <<*Iter1<<" ";
cout <<endl;
cout <<"\nThen, vector vec2 data is:\n";
for (Iter2 = vec2.begin(); Iter2 != vec2.end(); Iter2++)
cout <<*Iter2<<" ";
cout <<endl;

return 0;
}```
Solution
Output:

Vector vec1 data is:
10 11 12 13 14 15 16 17 18 19 20

Vector vec2 data is:
10 11 12 13 14 15

Now, vector vec1 data is:
10 11 12 13 14 15

Then, vector vec2 data is:
10 11 12 13 14 15 16 17 18 19 20
References