C Exercises: Check whether a number is positive or negative

Last update on July 29 2025 12:52:36 (UTC/GMT +8 hours)

3. Positive or Negative Check

Write a C program to check whether a given number is positive or negative.

Visual Presentation:

Sample Solution:

C Code:

#include <stdio.h>   // Include the standard input/output header file.

void main()
{
    int num;   // Declare an integer variable 'num'.

    printf("Input a number : ");   // Prompt the user to input a number.
    scanf("%d", &num);   // Read and store the user's input in 'num'.
    if (num >= 0)   // Check if 'num' is greater than or equal to 0.
        printf("%d is a positive number \n", num);   // Print a message indicating that 'num' is a positive number.
    else
        printf("%d is a negative number \n", num);   // Print a message indicating that 'num' is a negative number.
}

Output:

Input a number :15                                                                                            
15 is a positive number  

Flowchart:

For more Practice: Solve these Related Problems:

• Write a C program to check whether a number is positive, negative, or zero using only ternary operators.
• Write a C program to determine the sign of each number in an array without using conditional statements.
• Write a C program to compare two numbers and print which one is positive, negative, or zero.
• Write a C program to check a number’s sign by directly inspecting its sign bit.

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