This program is to find whether two numbers are of opposite sign. We will be using two approach to solve this:

First approach:
Simple Xor both the numbers and if result is less than 1 means the given two numbers are of opposite sign

#include <stdio.h>
int main()
{
  int num1, num2;
  printf("\n Enter the first number : ");
  scanf("%d",&num1);

  printf("\n Enter the second number :");
  scanf("%d",&num2);

  if ((num1 ^ num2) <1)
    printf("\n The given numbers have opp sign\n");
  else
    printf("\n The given numbers do not have opp sign\n");
return 0;
}

Output:

Enter the first number : 9
Enter the second number :8

The given numbers do not have opp sign

Second Approach:
Get the MSB bit of each number and Xor them, if the result is 1 means they are of opposite sign

#include <stdio.h>
     
int get_msb_bit(int num)
{
  int no_of_bits = sizeof(num) *8;
  if ((num >> no_of_bits -1) &1)
    return  1;
  else
    return 0;
}

int main()
{
  int num1, num2;
  printf("\n Enter the first number : ");
  scanf("%d",&num1);

  printf("\n Enter the second number :");
  scanf("%d",&num2);
  
  int res1 = get_msb_bit(num1);
  int res2 = get_msb_bit(num2);
  
  if (res1 ^res2)
     printf("\n The two numbers are of opposite sign");
  else
    printf("\n The two numbers are of same sign");
  return 0;

}

Output:

Enter the first number : 9
Enter the second number :-1


The two numbers are of opposite sign

The first approach is better than second.

Categories: C Language