C Program to Check Whether a Given Number is Even or Odd

As a beginner in programming, one of the first things you will learn is how to check whether a given number is even or odd. In this article, we will learn how to write a C program to check whether a given number is even or odd. We will start by discussing the concept of even and odd numbers, and then we will move on to writing the C program.

What are Even and Odd Numbers?

In mathematics, a number is said to be even if it is divisible by 2. On the other hand, a number is said to be odd if it is not divisible by 2. In simple words, if a number is divisible by 2 without leaving a remainder, it is even, and if not, it is odd.

For example, 4 is an even number because it is divisible by 2, while 5 is an odd number because it is not divisible by 2.

Writing a C Program to Check Whether a Given Number is Even or Odd

To check whether a given number is even or odd, we will use the modulo operator % in our C program. The modulo operator returns the remainder of the division of two numbers.

Here’s the C program to check whether a given number is even or odd:

				
					#include <stdio.h>

int main() {
    int num;

    printf("Enter an integer: ");
    scanf("%d", &num);

    if (num % 2 == 0) {
        printf("%d is even.", num);
    } else {
        printf("%d is odd.", num);
    }

    return 0;
}

				
			

Let’s break down the above program into smaller parts to better understand how it works:

Include Header Files

				
					#include <stdio.h>

				
			

The above line of code includes the standard input/output library in our program, which provides functions for input and output operations.

Define the Main Function

				
					int main() {
    // Code goes here
    return 0;
}
				
			

The main() function is the starting point of our program. It is a mandatory function in every C program.

Declare a Variable

				
					int num;
				
			

The above line declares a variable num of type int, which will store the number entered by the user.

Prompt the User for Input

				
					printf("Enter an integer: ");
scanf("%d", &num);
				
			

The above code prompts the user to enter an integer and reads the input entered by the user into the num variable using the scanf() function.

Check Whether the Number is Even or Odd

				
					if (num % 2 == 0) {
    printf("%d is even.", num);
} else {
    printf("%d is odd.", num);
}
				
			

The above code checks whether the number entered by the user is even or odd using the modulo operator %. If the remainder of the division of num by 2 is 0, it means that num is even, and the program prints the message num is even. Otherwise, it means that num is odd, and the program prints the message num is odd.

Return Statement

				
					return 0;
				
			

The return statement in the main() function terminates the program and returns a value of 0 to the operating system, indicating that the program ran successfully.

Conclusion

In this article, we learned how to write a C program to check whether a given number is even or odd. We started by discussing the concept of even and odd numbers and then went on to write the C program step by

A: A C program is a set of instructions that a computer can execute written in the C programming language.

A: The modulo operator % in C returns the remainder of the division of two numbers.

A: In mathematics, a number is said to be even if it is divisible by 2.

A: In mathematics, a number is said to be odd if it is not divisible by 2.

A: The scanf() function in the C program is used to read input entered by the user.

A: The printf() function in the C program is used to print output to the console.

A: Yes, a negative number can be even or odd. The sign of a number does not affect whether it is even or odd.

A: No, a decimal number cannot be even or odd. The concept of even and odd numbers only applies to integers.

A: No, the C program to check whether a number is even or odd cannot be used to check whether a number is prime. Checking whether a number is prime requires a different algorithm.

A: No, it is not necessary to include the standard input/output library in the C program to check whether a number is even or odd, but it is good practice to do so as it provides functions for input and output operations.

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