# Prime Number Program in C

Posted in  Vinay Khatri
Last updated on August 28, 2022

Here we will write a code in C language to check whether the entered number is a prime number or not. Here is a sample code of the Prime Number Program in C.

## What is a Prime number?

A natural number will be called a prime number if it is only divisible by 1 and itself. For example, 3 is a prime number because it is only divisible by 1 and itself.

### Steps

• First, we ask the user to enter a number
• Then we create a loop from 2 to half of that number.
• Inside the loop using the if statement we will check whether the entered number is divisible by any of number between 2 to half of the entered number.
• If the number is divisible by any of number between 2 to half of the entered number, we will break the loop and print the statement that the entered number is not a prime number.

### Statements used

• for loop
• break statement
• % (modules)
• if…..else

### Prime Number Program in C

``````#include<stdio.h>
#include<conio.h>
void main()
{
int num, i;
clrscr();
printf("Enter a number:");
scanf("%d",&num);
if(num==1 ||num==2)
printf("It is a Prime Number");
else{
for(i =2;i<=num/2;i++)
{
if(num%i==0)    //check whether num is divisible by i or not
{  printf("It is not a Prime Number");
break;
}
else
if(i==num/2)
printf("It is a prime number ");
}
}
getch();
}``````

Output:

``````Enter a number:49
It is not a Prime Number``````