C Program to Check Odd Number

Posted in C Tutorial

Updated on Jan 10, 2024

By Mari Selvan

👁️ 148 - Views

⏳ 4 mins

💬 1 Comment

Photo Credit to CodeToFun

🙋 Introduction

In the realm of programming, dealing with numbers is a fundamental task. One common requirement is checking whether a given number is odd or not.

An odd number is an integer that is not exactly divisible by 2 and leaves a remainder of 1 when divided by 2.

In this tutorial, we will explore a C program designed to check whether a given number is odd. The program involves using the modulo operator to determine if the number is not divisible by 2.

📄 Example

Let's delve into the C code that accomplishes this task.

odd.c

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#include <stdio.h>

// Function to check if a number is odd
int isOdd(int number) {
  // If the remainder is 1, the number is odd
  return number % 2 != 0;
}

// Driver program
int main() {
  // Replace this value with the number you want to check
  int number = 15;

  // Call the function to check if the number is odd
  if (isOdd(number))
    printf("%d is an odd number.\n", number);
  else
    printf("%d is not an odd number.\n", number);

  return 0;
}

💻 Testing the Program

To test the program with different numbers, modify the value of number in the main program.

Output

15 is an odd number.

🧠 How the Program Works

The program defines a function isOdd that takes an integer number as input and returns 1 (true) if the number is odd, and 0 (false) otherwise.
Inside the main program, replace the value of number with the desired number you want to check.
The program calls the isOdd function and prints the result.

📏 Between the Given Range

Let's take a look at the C code that checks and displays odd numbers in the specified range.

checkAndDisplayOddNumbers.c

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#include <stdio.h>

// Function to check and display odd numbers in the range 1 to 10
void checkAndDisplayOddNumbers() {
  printf("Odd Numbers in the range 1 to 10:\n");

  // Iterate through the range
  for (int i = 1; i <= 10; ++i) {
    // Check if the current number is odd
    if (i % 2 != 0) {
      printf("%d ", i);
    }
  }

  printf("\n");
}

// Driver program
int main() {
  // Call the function to check and display odd numbers
  checkAndDisplayOddNumbers();

  return 0;
}

💻 Testing the Program

Output

Odd Numbers in the range 1 to 10:
1 3 5 7 9

The range for this program is fixed from 1 to 10. To test the program, simply compile and run it.

🧠 How the Program Works

The program defines a function checkAndDisplayOddNumbers that iterates through the range from 1 to 10.
For each number in the range, it checks if the number is odd.
If the number is odd, it is displayed.

🧐 Understanding the Concept of Odd Number

Before delving into the code, let's understand the concept of odd numbers. An odd number is an integer that is not exactly divisible by 2. In other words, when an odd number is divided by 2, the remainder is 1.