C :

#include<stdio.h>
#include<math.h>
 int main()
{   
	 int i,k,m,T;   
	 scanf("%d",&T);
	 while(T--)
	 {
		
	 scanf("%d",&i);  
	 if(i<=1) printf("NO\n",i);
	 else
	 {
			 k=sqrt(i);
		  for(m=2;m<=k;m++)    
			if(i%m==0)break;     
			  if(m>k)    
				  printf("YES\n",i);   
			  else  
				  printf("NO\n",i);
			  }
	 }
	  return 0;
 }

C++ :

#include<stdio.h>
int main()
{
    int i,j,k;
    int t,n,m;
    scanf("%d",&t);
    while(t--)
    {
        int flag=1;
        scanf("%d",&n);
        if(n<=1)
        {
            printf("NO\n");
            continue;
        }
        for(i=2;i*i<=n;i++)
        {
            if(n%i==0)
            {
                flag=0;
                break;
            }
        }
        if(flag)
            printf("YES\n");
        else
            printf("NO\n");
    }
    return 0;
}

Java :

import java.util.Scanner;
public class Main{
public static boolean isPrime(int num) {
	if(num==0||num==1){
		num=4;
	}
  boolean prime = true;
  int limit = (int) Math.sqrt(num);
  for (int i = 2; i <= limit; i++) {
	  if (num % i == 0) {
    prime = false;
    break;
   }
  }
  return prime;
}
public static void main(String[] args) {
  Scanner input = new Scanner(System.in);
  int T = input.nextInt();
  for(int i=0;i<T;i++){
  int n = input.nextInt();
  if (isPrime(n)) {
   System.out.println("YES");
  } else {
   System.out.println("NO");
  }
}
}
}