Hollow Diamond of Stars

This program prints a hollow diamond of stars.

Problem Statement

Write a Java program that prints a hollow diamond of stars with 5 rows.

Source Code

1 public class HollowDiamond {
2 public static void main(String[] args) {
3 int n = 5;
4 for(int i=1; i<=n; i++) {
5 for(int j=i; j<n; j++) System.out.print(" ");
6 for(int k=1; k<=2*i-1; k++) {
7 if(k==1 || k==2*i-1) System.out.print("*");
8 else System.out.print(" ");
9 }
10 System.out.println();
11 }
12 for(int i=n-1; i>=1; i--) {
13 for(int j=i; j<n; j++) System.out.print(" ");
14 for(int k=1; k<=2*i-1; k++) {
15 if(k==1 || k==2*i-1) System.out.print("*");
16 else System.out.print(" ");
17 }
18 System.out.println();
19 }
20 }
21 }

Program Output

    *    
   * *   
  *   *  
 *     * 
*       *
 *     * 
  *   *  
   * *   
    *    

Explanation

The first half builds an upper hollow pyramid and the second builds an inverted hollow pyramid, printing stars only at boundaries with spaces inside, together forming a hollow diamond shape.

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