Inverted Right-Angled Triangle Star Pattern in Java

What You’ll Learn

The inverted right-angled triangle is the mirror of Program 1: same inner star loop, but the outer loop counts down so the widest line prints first. This tutorial covers reverse iteration, an equivalent forward-loop formula, a live preview, algorithm steps, worked Java examples, edge cases, and complexity.

📝 Problem & Approach

Given a positive integer rows, print a left-aligned inverted right-angled triangle of * characters with rows lines.

// First 5 rows (conceptual shape)
// *****
// ****
// ***
// **
// *

Inputs & Outputs

Minimal workflow

for i from rows down to 1:
    for j from 1 to i:
        print "*" (no newline)
    print newline

Approach comparison

🔮 Live Preview

Choose a row count between 1 and 20 and draw the inverted triangle in the browser.

Press "Draw pattern".

Examples Gallery

Three complete Java programs — countdown outer loop, Scanner input, and a forward-loop equivalent with "*".repeat(). Click View Output to reveal sample console results.

public class InvertedTriangle {
    public static void main(String[] args) {
        int rows = 5;
        int i, j;

        for (i = rows; i >= 1; i--) {
            for (j = 1; j <= i; j++) {
                System.out.print("*");
            }
            System.out.println();
        }
    }
}

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

import java.util.Scanner;

public class InvertedTriangleInput {
    public static void main(String[] args) {
        int rows;
        int i, j;
        Scanner sc = new Scanner(System.in);

        System.out.print("Enter the number of rows: ");
        rows = sc.nextInt();

        for (i = rows; i >= 1; i--) {
            for (j = 1; j <= i; j++) {
                System.out.print("*");
            }
            System.out.println();
        }

        sc.close();
    }
}

Enter the number of rows: 7
*******
******
*****
****
***
**
*

public class InvertedTriangleForward {
    public static void main(String[] args) {
        int rows = 5;

        for (int i = 1; i <= rows; i++) {
            int stars = rows - i + 1;
            System.out.println("*".repeat(stars));
        }
    }
}

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

🔎 Worked Walkthrough — rows = 4

Trace each outer-loop value of i as it counts down, and count how many times the inner loop runs.

Total star prints: 4 + 3 + 2 + 1 = 10 = 4×5/2 — same total as the upright triangle of height 4.

🎯 Practice Problems

Try these variations to lock in the pattern.

Notes

⏱️ Time and Space Complexity

💡 Best Practices