效果圖如下圖所示：

 1 package myeclipseFiles2;
 2 
 3 public class Rhombus {
 4 
 5     public static void main(String[] args) {
 6         // TODO Auto-generated method stub
 7         int i=1;
 8         while(i<=4){
 9             int j=1;
10             //先打印出前i+1個數
11             while(j<=i+3){
12                 //
 
判斷打印的數中前幾個數應該是打印空格
13                 if(j<=4-i){
14                     System.out.print(" ");
15                 }else{
16                     System.out.print("*");
17                 }
18                 j++;
19             }
20             System.out.println();
21             i++;
22         }
 
23         int i1=1;
24         while(i1<=3){
25             int j1=1;
26             while(j1<=7-i1){
27                 if(j1<=i1){
28                     System.out.print(" ");
29                 }else{
30                     System.out.print("*");
31                 }
32                 j1++;
 
33             }
34             System.out.println();
35             i1++;
36         }
37     }
38 
39 }

while循環打印*菱形