How to Implement Odd & Even Program in C

Checking whether a number is even or odd, is a very common problem in C language. Following pointers will be covered in this Odd & Even Program in C article:

• Odd & Even Program Flow Diagram
  
• Odd & Even Program Algorithm
  
• Odd & Even Program Pseudocode
  
• Program to Check Even or Odd
  
• Program to Check Odd or Even Using Conditional Operator
  
• Find Odd or Even Using Bitwise Operator

If a number is perfectly divisible by 2 it is known as even number. The remaining numbers which are not perfectly divisible by 2 is known as odd number. In simple words, even numbers are those numbers which are in form n = 2k, whereas odd numbers are those numbers which are in form of n = 2k+1. All the integers will either be even numbers or odd numbers. In this blog we will understand how to check whether a number is even or odd using C program.

There are various ways in which we can check whether a given number is even or odd.

Let’s look at each one of them one by one. 

Odd & Even Program Flow Diagram

Following would be the flow diagram for the odd or even program:

Now let us look at the algorithm for odd & even Program in C.

Odd & Even Program Algorithm

The algorithm is very simple:

START

   Step 1 → Take a integer n

   Step 2 → Assign n to the variable

   Step 3 → Perform n modulo 2 and check result if output is 0

   Step 4 → If true n is even

   Step 5 → If false n is odd

STOP

Now let us look at the algorithm for Odd & Even Program Pseudocode

Odd & Even Program Pseudocode

IF (integer modulo 2) equals to 0

   PRINT number is even

ELSE

   PRINT number is odd

END IF

Now let us look at the algorithm for Program to Check Even or Odd

Program to Check Even or Odd

In C programming language, we have a modulo operator which returns the remainder of the divisor & divident. We will use this operator to figure out whether the nuber is 2k format or 2k+1 format.

Now, let ius look at the code to check whether a given integer is odd or even.

Code

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

Moving ahead, let us look at the complete code.

Example

#include <stdio.h>
int main()
{
int num;
printf("Enter a numer: ");
scanf("%d", &num);
if(num % 2 == 0)
printf("%d is even.", num);
else
printf("%d is odd.", num);
return 0;
}

Output1:

Output2:

In this program we checked whether the given number is returning 0 or 1 remainder when we divide it with 2. If n%2==0, the number is even, else the number is odd.

Now let’s look at one more variation where you can perform the same.

Program to Check Odd or Even Using Conditional Operator

You can also use conditional operator to verify the same condition which we have discussed earlier.

Conditional Operator/Ternary operator: Conditional operators return one value if condition is true and returns another value is condition is false.

Syntax     :        (Condition? true_value: false_value);

Example :         (X > 10  ?  0  :  1);

Example

#include <stdio.h>
int main()
{
int num;
printf("Enter a numer: ");
scanf("%d", &num);
(num % 2 == 0) ? printf("%d is even.", num) : printf("%d is odd.", num);
return 0;
}

Output1:

Output2:

Let us look at one more variation

Find Odd or Even Using Bitwise Operator

You can also check whether the given number is even or odd using bitwise AND operator.

Example

#include <stdio.h>
int main()
{
int num;
printf("Enter a numer: ");
scanf("%d", &num);
if (num & 1 == 1)
printf("%d is odd.", num);
else
printf("%d is even.", num);
return 0;
}

Output1:

Output2:

Now after going through the above programs you would have understood how to check whether a given number is odd or even in C programming. I hope this blog is informative and added value to you.

With this, we come to an end of this Odd & Even Program in C article.

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