In this section you will learn how to write a C program to check whether it is prime or composite number or not.
For Eg. Enter an Integer Number : 47
The Number 47 is a Prime Number.
Now lets see the C Program to check whether it is prime/composite number or not.
Program
/* Program : Checking Prime/Composite Number */
#include <stdio.h>
#include <math.h>
#include <stdlib.h>
int main(){
int n, flag,s,i;
printf("\n\nEnter an integer number : ");
scanf("%d", &n);
if(n==1){
printf("The number %d is neither prime nor composite\n",n);
return 0;
}
s=sqrt(n);
flag=0;
for(i=2;i<=s;i++){
if(n%i==0){
printf("The Number %d is not a Prime Number(Composite Number)\n",n);
flag=1;
break;
}
}
if(flag==0)
printf("The Number %d is a Prime Number \n",n);
return 0;
}
Output :-
