C program to illustrate function with return value and no argument

Write a C program to swap two numbers without using temporary variable.

  #include <stdio.h>

  /* 
   * Function with return value and no args.
   * manipulate() - swaps two numbers without
   * temp variable
   */
  int manipulate()  {
        int a, b;

        /* get the input values from the user */
        printf("Enter your inputs:");
        scanf("%d%d", &a, &b);

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

        /* print the results */
        printf("After swapping:\n");
        printf("a = %d\nb = %d\n", a, b);
        return 1;
  }

  int main() {
        int flag;
        printf("Program to swap two numbers without temp variable\n");
        flag = manipulate();
        if (flag)
                printf("Operation success\n");
        else
                printf("Operation failure\n");
        return 0;
  }

  Output:

  jp@jp-VirtualBox:~/$ ./a.out
  Program to swap two numbers without temp variable
  Enter your inputs:100 200
  After swapping:
  a = 200
  b = 100
  Operation success