Java Program to Print Downward Right Triangle Number Pattern - 3

In this program we print a downward right triangle number pattern in which every row ends with the same number. The first row prints 1 to 5, the second starts at 2, the third at 3, and so on until the last row prints just 5.

Like every pattern program, it is built from nested loops: the outer loop picks the row, and the inner loop prints what goes on that row.

1. The Pattern

For 5 rows the program prints:

1 2 3 4 5
2 3 4 5
3 4 5
4 5
5

2. How the Program Works

Here is what each printed line is made of when numberOfRows is 5:

• The outer loop counts row up from 1 to numberOfRows.
• The inner loop starts column at row instead of 1 and runs up to numberOfRows, printing column followed by a space. Because the start moves one place right on every row while the end stays fixed, each row is one number shorter.
• Compare this with Number Pattern - 7, where the end of each row moves (1 to 5, 1 to 4, …) and the start stays at 1.
• System.out.println() moves to the next line after each row.

3. Java Program

public class Pattern9 {
    public static void main(String[] args) {
        int numberOfRows = 5;

        // outer loop for the rows
        for (int row = 1; row <= numberOfRows; row++) {
            // inner loop prints the numbers from row up to numberOfRows
            for (int column = row; column <= numberOfRows; column++) {
                System.out.print(column + " ");
            }
            // move to the next line
            System.out.println();
        }
    }
}

1 2 3 4 5
2 3 4 5
3 4 5
4 5
5

4. Print the Pattern for Any Number of Rows

To let the user choose the size of the pattern, read the number of rows with a Scanner. The loops stay the same.

import java.util.Scanner;

public class Pattern9Input {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.print("Enter the number of rows: ");
        int numberOfRows = scanner.nextInt();
        scanner.close();

        // outer loop for the rows
        for (int row = 1; row <= numberOfRows; row++) {
            // inner loop prints the numbers from row up to numberOfRows
            for (int column = row; column <= numberOfRows; column++) {
                System.out.print(column + " ");
            }
            // move to the next line
            System.out.println();
        }
    }
}

Enter the number of rows: 6
1 2 3 4 5 6
2 3 4 5 6
3 4 5 6
4 5 6
5 6
6

5. Summary

• The outer loop picks the row; the inner loop prints the numbers for that row.
• Starting the inner loop at row makes each row begin one number later, while every row still ends at numberOfRows.
• Keep numberOfRows in a variable, so the same program can print the pattern in any size.

Related Programs

• Java Program to Print Downward Right Triangle Number Pattern - 1
• Java Program to Print Downward Right Triangle Number Pattern - 2
• Java Program to Print Downward Left Triangle Number Pattern - 1
• Java Program to Print Left Triangle Number Pattern - 2
• All Java Pattern Programs