Odd or Even Number Checker in C

This program determines if a given number is odd or even. Below is the C code for the program along with a detailed explanation of its structure and documentation.

Program Code

#include <stdio.h>

/**
 * Function to check if a number is odd or even.
 * @param number - the number to be checked
 * @return 1 if the number is odd, 0 if the number is even
 */
int isOddOrEven(int number) {
    return number % 2;
}

int main() {
    int number;

    // Prompt the user to enter a number
    printf("Enter a number: ");
    scanf("%d", &number);

    // Check if the number is odd or even
    if (isOddOrEven(number)) {
        printf("The number %d is odd.\n", number);
    } else {
        printf("The number %d is even.\n", number);
    }

    return 0;
}

Explanation

Here’s a step-by-step explanation of the program structure:

1. Include Header File:

   #include <stdio.h>

   This header file is included to use the standard input-output functions like printf and scanf.

2. Function Definition:

   
   /**
    * Function to check if a number is odd or even.
    * @param number - the number to be checked
    * @return 1 if the number is odd, 0 if the number is even
    */
   int isOddOrEven(int number) {
       return number % 2;
   }
               

   The isOddOrEven function takes an integer as input and returns 1 if the number is odd, and 0 if the number is even. It uses the modulus operator (%) to determine the remainder when the number is divided by 2.

3. Main Function:

   int main() {
       int number;
   
       // Prompt the user to enter a number
       printf("Enter a number: ");
       scanf("%d", &number);
   
       // Check if the number is odd or even
       if (isOddOrEven(number)) {
           printf("The number %d is odd.\n", number);
       } else {
           printf("The number %d is even.\n", number);
       }
   
       return 0;
   }

   The main function is the entry point of the program.

   • It declares an integer variable number.
   • It prompts the user to enter a number using printf and reads the input using scanf.
   • It calls the isOddOrEven function to check if the number is odd or even and prints the result accordingly.
   • It returns 0 to indicate that the program ended successfully.