C++ Program to two swap two numbers without using third variable

C++ Program to swap two numbers without third variable

We can swap two numbers without using third variable. There are two common ways to swap two numbers without using third variable:

1. By using + and - operators.

Program:

#include <iostream>
using namespace std;

int main()
{
    int a,b;
    cout<<"a=";
    cin>>a;
    cout<<"b=";
    cin>>b;
    
    a=a+b;
    b=a-b;
    a=a-b;
    
    cout<<"After swap:"<<endl;
    cout<<"a="<<a<<" b="<<b;
    
    return 0;
}

Output:

a=10

b=20

After swap

a=20 b=10

 2. By using * and / operators.

Program:

#include <iostream>
using namespace std;

int main()
{
    int a,b;
    cout<<"a=";
    cin>>a;
    cout<<"b=";
    cin>>b;
    
    a=a*b;
    b=a/b;    
    a=a/b;
    
    cout<<"After swap:"<<endl;
    cout<<"a="<<a<<" b="<<b;
    
    return 0;
}

Output:

a=10

b=20

After swap

a=20 b=10