C Exercises: Check the given number is even or odd

Last update on March 20 2025 12:33:33 (UTC/GMT +8 hours)

4. Even/Odd Check Function Variants

Write a program in C to check if a given number is even or odd using the function.

Pictorial Presentation:

C Exercises: Check the given number is even or odd

Sample Solution:

C Code:

#include <stdio.h>
 
//if the least significant bit is 1 the number is odd and 0 the number is even 
int checkOddEven(int n1)
{   
    return (n1 & 1);//The & operator does a bitwise and,
}

int main()
{
    int n1;
	printf("\n\n Function : check the number is even or odd:\n");
	printf("------------------------------------------------\n");	     
    printf("Input any number : ");
    scanf("%d", &n1);

    // If checkOddEven() function returns 1 then the number is odd 
    if(checkOddEven(n1))
    {
        printf("The entered number is odd.\n\n");
    }
    else
    {
        printf("The entered number is even.\n\n");
    }
    return 0;
}

Sample Output:

 Function : check the number is even or odd:
------------------------------------------------
Input any number : 5
The entered number is odd.

Explanation:

int checkOddEven(int n1) {
   return (n1 & 1); //The & operator does a bitwise and,
 }

The above function 'checkOddEven' takes a single argument of type int, named 'n1'. It checks whether the value of 'n1' is odd or even by performing a bitwise AND operation between 'n1' and the binary value 1.

If the result of this operation is 1, then the least significant bit of n1 is 1, which means that n1 is odd.

If the result is 0, then the least significant bit of n1 is 0, which means that n1 is even. The function then returns the result of as an integer value of 0 (even) or 1 (odd).

Time complexity and space complexity:

The time complexity of the function ‘checkOddEven’ is O(1), as the computation it performs is constant and independent of the input size.

The space complexity of this function is also O(1), as it only uses a fixed amount of memory to store the single integer variable n1.

Flowchart:

For more Practice: Solve these Related Problems:

Write a C program that returns a string ("Even" or "Odd") from a function after checking a number’s parity.
Write a C program to determine if a number is even or odd using bitwise operations in a function.
Write a C program that uses a function to check if a number is even, odd, or zero and prints an appropriate message.
Write a C program to count the even and odd numbers in an array by invoking a parity-check function on each element.

C Programming Code Editor:

Previous: Write a program in C to swap two numbers using the function.
Next: Write a program in C to find the sum of the series 1!/1+2!/2+3!/3+4!/4+5!/5 using the function.