C++ program to Swap two numbers

C++ program to Swap two numbers

Once again we discuss about one of the most basic and important C++ Programs which is frequently ask in any interview or exam. To write swap two numbers program in C++ is very simple and easy just you need 3 variable and = operator. Swap numbers means exchange the values of two variables with each other. For example variable num1 contains 200 and num2 contains 400 after swap there values num1 contains 400 and num2 contains 200.

Example: Suppose we have three glass A, B, Temp. Glass A contain ball printed 30, Glass B contain ball printed 50 and Glass Temp is empty now we want to interchange these two glass (A, B) ball. So we follow below steps...

• First we take Glass A and there ball 30 place inside Glass Temp
• Now Glass A is empty, take Glass B and there ball 50 place inside Glass A.
• Now Glass B is empty, take Glass Temp and there ball 30 place inside Glass B
• Finally Both Glass values are exchange, Glass A contain ball 50 and Glass B contain ball 30.

Swap two numbers using third variables

#include<iostream.h>
#include<conio.h>

void main()
{
int a,b,c;
clrscr();
cout<<"Enter value of a: ";
cin>>a;
cout<<"Enter value of b: ";
cin>>b;
c=a;
a=b;
b=c;
cout<<"After swap a: "<<a<<"b: "<<b;
getch();
}

Enter value of a: 10
Enter value of b: 20
After swap a: 20 b: 10

Swap two numbers without using third variable

#include<iostream.h>
#include<conio.h>

void main()
{
int a,b;
clrscr();
cout<<"Enter value of a: ";
cin>>a;
cout<<"Enter value of b: ";
cin>>b;
a=a+b;
b=a-b;
a=a-b;
cout<<"After swap a: "<<a<<"b: "<<b;
getch();
}

Enter value of a: 10
Enter value of b: 20
After swap a: 20 b: 10