/*
 * Project1.c
 * Chapter 9
 * By John Stile
 * Purpose: A logical operator not found in C is exclusive-or (XOR)
 *   Logic: TRUE if and only if one sub-expression is TRUE
 *
 * Write a function xor() that takes two expressions that evaluate to integers,
 * and returns int 1 if one of the expressions evalutates to true
 */
#include <stdio.h>
#include "Project1.h"

// xor function: one and only one can be true
int xor(int aa, int bb)
{
  if ( (aa>1) || (bb>1) ) // check that they endered valid number
  {  
    printf("I asked for input of 0 or 1!!!\n");
    printf("Result will be unreliable\n");
    return 0;
  }

  if (aa)  // if aa is true, do block
  {
    if (bb) // if bb is also true, do block
    {
      // both true, return 0
      return 0;
    }  
    else
    {
      // one is true, return 1
      return 1;
    }
  }
  else 
  {
    if (bb) // only one is true,  return 1
    {
      return 1;
    }
    else  // both false, return 0
    {
      return 0;
    } 
  }
}