Java Program to Print Right Triangle Number Pattern

• Java program to print right triangle number pattern.

A right triangle number pattern contains N space separated consecutive natural numbers in Nth row.

Sample triangle pattern of 5 rows.

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

Here is the matrix representation of the right triangle number pattern. The row numbers are represented by i whereas column numbers are represented by j.

Algorithm to print right triangle number pattern

• There are N natural numbers in N^th Row. 1^st row contains 1 number, 2^nd row contains 2 numbers etc.
• In any row N, the numbers start from 1 and continue till N in increment of 1. For example, 4th row contains numbers from 1 to 4.
• We will use two for loops to print right triangle number pattern.
  • For a right triangle number pattern of N rows, outer for loop will iterate N time(from i = 1 to N). Each iteration of outer loop will print one row of the pattern.
  • The inner for loop will print all elements of a row. As we know that N^th row contains N elements from 1 to N. Hence, inner for loop will iterate from N times(j = 1 to N). Each iteration of inner for loop will print consecutive numbers starting from 1.

Java program to print right triangle number pattern

package com.tcc.java.programs;

import java.util.Scanner;

public class TrianglePattern {
    public static void main(String[] arg) {
        int rows, i, j;
        Scanner scanner = new Scanner(System.in);
        System.out.println("Enter Number of Rows of Pattern");
        rows = scanner.nextInt();
        
        /* Outer for loop prints one row in every iteration */
        for (i = 1; i <= rows; i++) {
            /* Inner for loop prints numbers of one row */
            for (j = 1; j <= i; j++) {
                System.out.print(j + " ");
            }
            System.out.print("\n");
        }
    }
}

Output

Enter Number of Rows of Pattern
5
1 
1 2 
1 2 3 
1 2 3 4 
1 2 3 4 5