C program to check whether a number is positive, negative or zero

Write a C program to check positive, negative or zero. C program to input any number from user and check whether the given number is positive, negative or zero. How to check negative, positive or zero using if else in C program. Logic to check negative, positive or zero in C program.

Input number: 23

23 is positive

Required knowledge

Basic programming, Basic mathematics, Use of relational operator, If else

Logic to check positive, negative or zero

Logic to this program is simple if you know basic maths. Let us first see some facts about numbers.

• A number is said to be negative if it is less than 0 i.e. n < 0.
• A number is said to be positive if it is greater than 0 i.e. n > 0.

Below is the step by step descriptive logic to check positive, negative or zero -

1. Read a number from user in some variable say num.
2. Check if num < 0. If it is then the number is negative. Hence print negative number.
3. Check if num > 0. If it is then the number is positive. Hence print positive number.
4. If the given number is neither positive nor negative. Then the number is zero. Hence print zero for this case.

Let us code the solution of this program.

Program to check positive, negative or zero

/**
 * C program to check positive negative or zero
 */

#include <stdio.h>

int main()
{
    int num;
    
    /* Read number from user */
    printf("Enter any number: ");
    scanf("%d", &num);
    

    if(num > 0)
    {
        printf("Number is POSITIVE");
    }
    else if(num < 0)
    {
        printf("Number is NEGATIVE");
    }
    else
    {
        printf("Number is ZERO");
    }

    return 0;
} 

Enter any number: 10
Number is POSITIVE

Happy coding ;)