




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:

By + and -
By * and /

Program 1: Using * and /
Let's see a simple C++ example to swap two numbers without using third variable.

 #include <iostream>
using namespace std;
int main()
{
int a=5, b=10;    
cout<<"Before swap a= "<<a<<" b= "<<b<<endl;    
a=a*b; //a=50 (5*10)  
b=a/b; //b=5 (50/10)  
a=a/b; //a=10 (50/5)  
cout<<"After swap a= "<<a<<" b= "<<b<<endl;    
return 0;
}

Output:

Before swap a= 5 b= 10     
After swap a= 10 b= 5





Program 2: Using + and -
Let's see another example to swap two numbers using + and -.

#include <iostream>
using namespace std;
int main()
{
int a=5, b=10;    
cout<<"Before swap a= "<<a<<" b= "<<b<<endl;    
a=a+b; //a=15 (5+10)  
b=a-b; //b=5 (15-10)  
a=a-b; //a=10 (15-5)  
cout<<"After swap a= "<<a<<" b= "<<b<<endl;    
return 0;
}

Output:

Before swap a= 5 b= 10  
 After swap a= 10 b= 5













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