Design and test a C program to swap two numbers using a third variable and without using a third variable.

With third variable (temp variable)

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

    // value of first is assigned to temp
    temp = first;

    // value of second is assigned to first
    first = second;

    // value of temp (initial value of first) is assigned to second
    second = temp;

    printf("\nAfter swapping, first number = %d\n", first);
    printf("After swapping, second number = %d\n", second);
    return 0;
}
Output


Without third variable

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

    first = first + second;
    second = first - second;
    first = first - second;

    printf("\nAfter swapping, first number = %d\n", first);
    printf("After swapping, second number = %d\n", second);
    return 0;
}
Output



Try to understand logic