Swap Two Numbers in C

In this example of swapping two numbers, the user will be requested to enter two numbers. These numbers will be then swapped by using a temporary variable “temp“.

#include <stdio.h>
#include <math.h>

int main() 
{
    int x, y, temp;
    
    printf("Please enter the first number: ");
    scanf("%d", &x);
    
    printf("Please enter the second number: ");
    scanf("%d", &y);
    
    printf("\nBefore swap:\n"); // Values before swapping
    printf("x: %d\n", x);
    printf("y: %d\n", y);
    
    temp = x; // Assigning the values of x to "temp"
    x = y; // Assigning the value of y to x
    y = temp; // Assigning the value of the temp variable to y
    
    printf("\n");
    
    printf("After swap:\n"); // Values after swapping
    printf("x: %d\n", x);
    printf("y: %d\n", y);
    return 0;
}

First, three variables namely x , y and temp will be declared. Next, the user will be asked to enter two numbers which will be stored in x and y respectively. The values of x and y will be displayed on the screen as they are before swapping.

    printf("\nBefore swap:\n"); // Values before swapping
    printf("x: %d\n", x);
    printf("y: %d\n", y);
    
    temp = x; // Assigning the values of x to "temp"
    x = y; // Assigning the value of y to x
    y = temp; // Assigning the value of the temp variable to y

The swapping algorithm works in the following manner. First, the value of x will be assigned to the temp variable which currently was empty. Then the value of y will be assigned to x because we already have stored the value of x in temp. Finally, the value stored in temp will be assigned to y and this is how easily we can swap the values of two numbers stored in two different variables. Next, the values of both x and y will be displayed on the screen after swapping.

Output

Before swap:
x: 7
y: 3

After swap:
x: 3
y: 7