Spiral Star Pattern

This program prints stars arranged in a spiral inside a square.

Problem Statement

Write a Java program that prints a 5x5 spiral star pattern.

Source Code

1 public class SpiralStarPattern {
2 public static void main(String[] args) {
3 int n = 5;
4 char[][] arr = new char[n][n];
5 int top=0, left=0, bottom=n-1, right=n-1;
6 while(top<=bottom && left<=right) {
7 for(int i=left; i<=right; i++) arr[top][i]='*';
8 top++;
9 for(int i=top; i<=bottom; i++) arr[i][right]='*';
10 right--;
11 for(int i=right; i>=left; i--) arr[bottom][i]='*';
12 bottom--;
13 for(int i=bottom; i>=top; i--) arr[i][left]='*';
14 left++;
15 }
16 for(int i=0; i<n; i++) {
17 for(int j=0; j<n; j++) System.out.print(arr[i][j] + " ");
18 System.out.println();
19 }
20 }
21 }

Program Output

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

Explanation

The same spiral boundary logic fills the outermost layer with stars only, so the four boundary loops trace only the outline of the square, forming a spiral star outline rather than a fully filled spiral.

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