C Program to Swap Two Numbers

In this program, we will see how we can swap the values of two variables in C. To understand this program, you should
know about the following topics in C:

• Data types
• Operators
• Input / Output

We shall take two approaches, one by using a third variable and other by not using any other variable.

Program 1: By using a temporary third variable

#include <stdio.h>
int main()
{
    int x, y, temp;
    printf("Enter first number ");
    scanf("%d", &x);
    printf("\nEnter second number ");
    scanf("%d", &y);

    temp = x;
    x = y;
    y = temp;

    printf("\nThe values after Swapping: x = %d, y = %d", x, y);

    return 0;
}

Explanation of the program

• First of all we have declared three integer type variables named x, y, and temp. x and y will be used to store the two input numbers while the variable temp will be used to swap the values of x and y.
• Then using the printf and scanf functions, two inputs are taken from the user. The first input will be stored in x and tghe second will be stored in y.
• Then temp variable will be assigned the value of x, x will be assigned the value of y and y will be assigned the value of temp. Doing this, the values of x and y will be swapped.
• Finally, the new values of x and y as the output message will be displayed using the printf function.

Program 2: Without using any third variable

#include <stdio.h>
int main()
{
    int x, y;
    printf("Enter first number ");
    scanf("%d", &x);
    printf("\nEnter second number ");
    scanf("%d", &y);

    a = a - b
    b = a + b
    a = b - a

    printf("\nThe values after Swapping: x = %d, y = %d", x, y);

    return 0;
}