C program to swap two numbers using 2 variables

#include <stdio.h>

int main() {
  int a, b;
  printf("Enter two numbers: ");
  scanf("%d %d", &a, &b);
  printf("Before swapping: a = %d, b = %d\n", a, b);

  // swap the values of a and b using two variables
  a = a + b;
  b = a - b;
  a = a - b;

  printf("After swapping: a = %d, b = %d\n", a, b);
  return 0;
}

Explanation

In this program, we first declare two integer variables a and b. Then we ask the user to input two numbers using the scanf() function. We print the original values of a and b using the printf() function.

To swap the values of a and b using two variables, we use the following steps:

1. Add a and b and store the result in a: a = a + b;
2. Subtract b from a and store the result in b: b = a – b;
3. Subtract the original value of b from a and store the result in a: a = a – b;

Finally, we print the swapped values of a and b using the printf() function.