# 5+ C Prime Number Checker Program Examples

This post contains a total of 5+ Hand-Picked C Prime number checker Program Examples with Source Code. All these prime number checker programs are made using C Programming Language.

You can use the source code of these examples with credits to the original owner.

### Related Posts

C Prime Number Checker Programs

### 1. By suman Dhakal

Made by suman Dhakal. Simple C Program to check if an entered number is prime. Source

```3
it is a prime number```
``````#include <stdio.h>
void main(){int a,j;scanf("%d",&a);

for(j=2;j<a;j++){ if(a%j==0)break;}

if(j==a)printf("it is a prime number");

else printf("it is not a prime number");}``````

### 2. By Prasanth Naidu Karaka

Made by Prasanth Naidu Karaka. Source

```entered number is : 10
it is not a prime number```
``````#include <stdio.h>
int main() {
int x,y,z=0;
scanf("%d",&x);
printf ("entered number is : %d \n",x);
if(x<0){
}
if(x==1){
printf ("it is neither prime number nor a composite number");

}
if(x>1){
for( y=2;y<x;y++){
if(x%y==0){
printf ("it is not a prime number");
z++;
break;

}

}

if(z==0){
printf ("it is a prime number");
}}
printf ("\n\n\n\n")  ;
printf ("please upvote if you like");
return 0;
}``````

### 3. By Akshat Vyas

Made by Akshat Vyas. Entering a positive number will give you the output whether the number is prime or not. Source

```Enter a positive integer: 10
10 is not a prime number.```
``````#include <stdio.h>

int main() {

int n, i, flag = 0;
printf("Enter a positive integer: ");
scanf("%d", &n);

// 0 and 1 are not prime numbers
// change flag to 1 for non-prime number
if (n == 0 || n == 1)
flag = 1;

for (i = 2; i <= n / 2; ++i) {

// if n is divisible by i, then n is not prime
// change flag to 1 for non-prime number
if (n % i == 0) {
flag = 1;
break;
}
}

// flag is 0 for prime numbers
if (flag == 0)
printf("%d is a prime number.", n);
else
printf("%d is not a prime number.", n);
printf("\nUpvote if you like 🥰");
return 0;
}``````

### 4. By Nossair el Katouri

Made by Nossair el Katouri. Source

```15
15 : Not a prime number```
``````#include<stdio.h>
int main()
{
int N,i,j,m,x;float r;
scanf("%d",&N);
r=1;
for(i=1;i<=100;i++)
{
r=(r/2)+(N/(2*r));
}
m=r;
m=m+1;
x=0;
for(j=2;j<=m;j++)
{
if(N%j>0)
{
x=x*1;
}
else
{
x=x+1;
}
}
if(x>0)
{
printf("%d : Not a prime number",N);
}
else
{
printf("%d : is a prime number",N);
}

}``````

### 5. By Charan Leo

```enter any no3-3
:3
prime no```
``````#include <stdio.h>

int main() {
int c=2,no;
printf ("enter any no");
scanf("%d",&no);

while(no%c!=0)
{
c++;
printf("%d-%d \n",no,c);
}
if(no==c)
{
printf (":%d\nprime no",no);
}
else
{
printf (":%d\nNot prime",no);
}
return 0;
}``````

### 6. By Sharon Shelton

Made by Sharon Shelton. Basic Prime Number Checker program using C. Source

```Enter the number to be checked:12
12 is not a prime number```
``````#include <stdio.h>

int main() {
int n,i,count=0;
printf("Enter the number to be checked:");
scanf("%d",&n);
for(i=1;i<=n;i++)
{
if(n%i==0)
count++;
}
if(count==2)
printf("%d is a prime number",n);
else
printf("%d is not a prime number",n);
return 0;
}``````