C Program to Check Whether a Number is Positive or Negative

In this example, you will learn to check whether a number (entered by the user) is negative or positive.

To understand this example, you should have the knowledge of following C programmingtopics:

• C Programming Operators
• C if…else Statement

This program takes a number from the user and checks whether that number is either positive or negative or zero.

Example #1: Check if a Number is Positive or Negative Using if…else

#include <stdio.h>
int main()
{
    double number;

    printf("Enter a number: ");
    scanf("%lf", &number);

    if (number <= 0.0)
    {
        if (number == 0.0)
            printf("You entered 0.");
        else
            printf("You entered a negative number.");
    }
    else
        printf("You entered a positive number.");
    return 0;
}

You can also solve this problem using nested if else statement.

Example #2: Check if a Number is Positive or Negative Using Nested if…else

#include <stdio.h>
int main()
{
    double number;

    printf("Enter a number: ");
    scanf("%lf", &number);

    // true if number is less than 0
    if (number < 0.0)
        printf("You entered a negative number.");

    // true if number is greater than 0
    else if ( number > 0.0)
        printf("You entered a positive number.");

    // if both test expression is evaluated to false
    else
        printf("You entered 0.");
    return 0;
}

Output 1

Enter a number: 12.3
You entered a positive number.

Output 2

Enter a number: 0
You entered 0.

Check out these related examples:

• • Convert Octal Number to Decimal and vice-versa

• • Convert Binary Number to Decimal and vice-versa

• • Demonstrate the Working of Keyword long

• • Calculate the Power of a Number

• • Find Factorial of a Number
  • Check Armstrong Number

• • Count Number of Digits in an Integer

• • Check Whether a Number is Prime or Not

• • Check Prime or Armstrong Number Using User-defined Function

• • Display Factors of a Number