HW5.30

 1 public class Solution
 2 {
 3     public static void main(String[] args)
 4     {
 5         for(int i = 3; i <= 1000; i++)
 6             if(isDoublePrime(i))
 7                 System.out.println("(" + i + ", " + (i + 2) + ")");
 8     }
 9
10     public static boolean isDoublePrime(int n)
11     {
12         if(isPrime(n) && isPrime(n + 2))
13             return true;
14         else
15             return false;
16     }
17
18     public static boolean isPrime(int n)
19     {
20         if(n == 1)
21             return false;
22         else if(n == 2)
23             return true;
24         else
25         {
26             for(int i = 2; i < n; i++)
27             {
28                 if(n % i == 0)
29                     return false;
30             }
31             return true;
32         }
33     }
34 }