int number = 0, check = 1;
cin>>number;
for(int i = 2; i < number; i++){
    if(div(number, i).rem != 0){
      check = 0;
      break;
    }
}
if(check){
    cout<<"Простое";
}else{
    cout<<"Непростое";
}

#include <stdio.h>
#include <stdlib.h>

#define SIZE 100
#define EXIT 0

int entered = 0;

void printArr(int arr[]);

int main(void)
{
      int numArr[SIZE]; //Ìàññèâ ÷èñåë
      int num = 0;
      int i;
        
      printf("Input.\n");
      for(i = 0; i < SIZE; i++)
      {
          printf("Element[%d]: ", (i + 1));
          scanf("%d", &num);
          numArr[i] = num;
          entered++;
            
          if(num == EXIT)
          {
              printArr(numArr);
              break;
          }
      }
        
      system("PAUSE");
      return 0;
}

void printArr(int arr[])
{
      int i;
      printf("\nOutput.\n");
      for(i = 0; i < entered; i++)
      {
          printf("Element[%d]: %d\n", (i + 1), arr[i]);
      }
}