1. C Programming for Beginners: Writing Your First Hello World Program in C in 2023 2. Mastering Datatypes in C Programming: A Comprehensive Guide for Beginners in 2023 3. Complete Guide to % Format Specifiers in C for Beginners in 2023 4. A Comprehensive Guide to Operators in C Programming: Learn Everything About Operators in C in 2023 5. Master C Operator Precedence and Associativity in 2023: Definition, Examples, and Code 6. Learn Increment and Decrement Operators in C: A Beginners Guide with Examples - Codzify 7. Mastering Bitwise Operators in C: A Comprehensive Guide with Examples - Codzify 8. Ternary Operators in C Programming: A Beginners Guide (2023) 9. Switch Statements in C 2023: Complete Guide for Beginners 10. Learn Functions in C Programming - A Complete Tutorial for Beginners in 2023 11. Call by Value and Call by Reference in C Programming - A Complete Tutorial for Beginners in 2023 12. Storage Classes in C Programming: A Comprehensive Guide for 2023 13. Arrays in C Programming: A Comprehensive Guide for 2023 14. Basics of 2D Array in C Programming in 2023: Definition, Initialization, and Accessing Elements 15. Beginners Guide to Strings in C Programming with Codes and Examples 16. Strings Functions in C Language - strlen, strcpy,strcmp,strcat functions 17. A Comprehensive Guide to Structures in C Programming in 2023 18. Learn Unions in C Programming with Codes, Examples, and Explanations in 2023 19. Dynamic Memory Allocation in C: Understanding malloc, calloc, realloc, and free Functions 20. Introduction to C Programming 21. Hello world program in C 22. String functions in C - strncat, strcpy, strncpy, strchr, strrchr, strstr functions 23. Program for Fibonacci number in C - Codzify.com 24. What is palindrome number in C? 25. Write a C program to find a factorial of a given number 26. Write a C program to check whether a given number is prime or not 27. Write a C program to check whether a given number is an Armstrong number or not. 28. Write a C Program to transpose a matrix 29. C Programming Tutorial: Understanding Comments and Identifiers with Code Examples 30. Master String Handling Functions in C in 2023 - Codzify Topics

Write a C program to check whether a given number is prime or not

Article by: Manish Methani

Last Updated: September 27, 2021 at 8:04am IST
2 min 13 sec

prime number is a number greater than 1 with only two factors – themselves and 1. 

A prime number cannot be divided by any other numbers without leaving a remainder.

An example of a prime number is 13. It can only be divided by 1 and 13. Dividing a prime number by another number results in numbers left over e.g. 13 ÷ 6 = 2 remainder 1.

15 is not an example of a prime number because it can be divided by 5 and 3 as well as by itself and 1.

C program to check whether a given number is prime or not.

#include 
int main()
{
    int number = 7;
    char flag = 0;
    for(int i = 2; i <= (number/2); i++)
    {
      if(number % i == 0)
      {
         flag = 1;
         break;
      }
    }

if (number == 1)
{
   printf("1 is neither prime nor composite.");
}
else
{
  if(flag == 0)
     printf("
%d is a prime number.", number);
  else
     printf("
%d is not a prime number.", number);
}

return 0;
}

Output

7 is a prime number.

In this program, a loop is iterated from 2 to number/2. In each iteration, using the condition (number % i) it is checked whether a given number is perfectly divisible by i. 

If a number is perfectly divisible by i, then the flag is set to 1 and break. After iteration, we will check whether a given number is 1 or not. if it is 1, the number is considered as a non-prime number else, if the flag is 0, then the given number is a prime number else the number is not a prime number.

Learn Flutter, FlutterFlow,
Firebase & Angular.

Looking to learn how to create the production-ready apps
from scratch? Well, you are at the right place.

₹1299 or $15.56

Learn to create the Dating App using No-Code Tool FlutterFlow

Level: Advanced

Explore Curriculum
₹1299 or $15.56

Flutter Mobile App Development Course

Explore Curriculum
₹1299 or $15.56

The Complete Angular Course

Explore Curriculum
₹1299 or $15.56

Dart Programming for Absolute Beginners

Coming Soon
FREE

Next.js course

Start Watching
FREE

Fundamentals of Computer Programming Languages

Start Watching
FREE

Learn HTML, CSS & Bootstrap

Start Watching

Latest Web Stories

1

Learn how to open WhatsApp using FlutterFlow | Step by Step Guide

Test your skills with these expert-led curated
Mock Tests.

C Programming Test

Test your C Programming skills with this comprehensive mock test on C Programming.

Take Test

Flutter Test

Solve most asked Interview Questions on Flutter and Test your foundational skills in flutter.

Take Test

GATE(CSE) Operating Systems

Solve most asked GATE Questions in Operating Systems and test your Gate Score.

Take Test

HTML,CSS Test

This is a mock test designed to help you assess your knowledge and skills in HTML and CSS.

Take Test

(GATE CSE) Data Structures & Algorithms Test

Solve most asked GATE Questions in Data Structures and Algorithms and test your Gate Score.

Take Test

Download the Codzify
Mobile App


Learn Anytime, Anywhere at your own pace. Scan the QR Code with your Mobile Camera to Download the Codzify Mobile App.

Codzify Mobile App Codzify Mobile App
Codzify Logo

Terms and Conditions    Cookie Policy   Refund Policy   Adsense Disclaimer