1    package j2d.examples; 
2     
3    /** 
4     * DocJava, Inc. User: lyon Date: Apr 25, 2004 
5     * Time: 8:44:49 AM 
6     */ 
7    public class BorderMath { 
8        public static void testBorder(int n) { 
9            for (int x=-10; x<10; x++){ 
10               System.out.println(x +"="+wrapX(x, n)); 
11    
12           } 
13       } 
14    
15       public static int wrapX(int x, int n) { 
16           if (x>=0) return x%n; 
17           //int i = n+x%n; 
18           //if (i== n) return 0; 
19           return (n+x%n)%n; 
20       } 
21    
22       public static void main(String[] args) { 
23           testBorder(6); 
24       } 
25   } 
26