**Contents**hide

## A Comprehensive Guide on Prime Numbers in C

## What is a prime number in C?

A prime number in C programming is a natural number bigger than one with no positive divisors other than 1 and itself. A prime number is one that cannot be equally divided by any other number except 1 and the number itself. 2, 3, 5, 7, 11, and 13 are prime numbers since they have no divisors other than 1 and the numbers themselves.

#### Example 1

#include<stdio.h> void main () { int i,n,f=0,count=1; printf("Enter a number:"); scanf("%d",&n); for(n=1;i<=100;n++){ for(i=2;i<n;i++){ if(n%i==0){ f++; break; } } } if(f==0) {printf("prime number ");} else { printf("prime not number ");} }

### Prime number in C using function

#### Example 2

#include<stdio.h> int prime(int num) { int i,count=0; for(i=2;i<num;i++){ if(num%i==0){ count++; break; } } if(count==0){ printf(" prime number"); } else printf("not prime number"); } void main () { int n,Prime; printf("Enter a number:"); scanf("%d",&n); Prime=prime(n); }

## C Programming

## FAQ

### How can I make the prime number checking function more efficient?

To improve the prime number verification function, limit the loop to run until the square root of the number being examined is reached. This is due to the fact that if a number has a divisor greater than its square root, it must also have a matching factor less than its square root.

### Is it possible to find even prime numbers in C?

Yes, C has one even prime number, which is 2. Because all other even numbers have 2 as a divisor, it is the only even prime number.