C program to check if a number is positive,negative or zero using macros

C programming to check if a number is positive, negative or zero using macros :

In this programming tutorial, we will learn how to check if a user input number is zero, negative or positive. Our program will ask the user to enter a number. Then it will check if the number is zero, positive or negative using a macro function. Let’s take a look at the program first :

C program :

#include<stdio.h>

//1
#define ISZERO(number) (number == 0)
#define ISPOSITIVE(number) (number > 0)
#define ISNEGATIVE(number) (number < 0)


int main(){
  int num;

  //2
  printf("Enter a number : ");
  scanf("%d",&num);

  //3
  if(ISZERO(num)){
    printf("It is a zero.");
  }else if(ISPOSITIVE(num)){
    printf("It is a positive number.");
  }else if(ISNEGATIVE(num)){
    printf("It is a negative number.");
  }
  
  return 0;
}

Explanation :

The commented numbers in the above program denote the step number below :

1. Create three different macros to check if the number is zero, positive or negative.
2. Ask the user to enter a number. Read it and store it in variable num.
3. Now using three if-else if conditions, check if the number is zero, positive or negative. Also, print out one message if any of these three checks is true.

Sample Output :

Enter a number : 0
It is a zero.
Enter a number : 3
It is a positive number.
Enter a number : -4
It is a negative number.