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.
Example
Example
#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:
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 -.
Example
Example
#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:
Output
Before swap a= 5 b= 10
After swap a= 10 b= 5