Prime Number Check
#include <stdio.h> int isprime(int n) { if(n==2 || n==3) return 1; if(n==1 || n%2==0 || n%3==0) return 0; for (int i=5;i<=sqrt(n);i=i+6) { if(n%i==0 || n%(i+2)==0) return 0; } return 1; } int main() { printf("%d\n",isprime(57)); printf("%d",isprime(61)); return 0; }