Java Program to Print Right Triangle Star Pattern

  • Write a Java program to print right angled triangle star pattern.

A Right triangle star pattern contains N space separated '*' characters in Nth row. In this program, we will use two for loops, outer for loop will print one row in every iteration whereas inner for loop will print N '*' characters for Nt row.

Sample Output
*
* *
* * *
* * * *
* * * * *
Algorithm to print right triangle star pattern
  • Take the number of rows of right triangle as input from user and store it in an integer variable N
  • Number of star characters in Kth row is always K. 1st row contains 1 star, 2nd row contains 2 stars. In general, Kth row contains K stars.
  • We will use two for loops to print right triangle star pattern.
    • Each iteration of outer loop will print one row of the pattern. For a right triangle star pattern of N rows, outer for loop will iterate N time.
    • Each iteration of inner loop will print one star (*). For Kth row of right triangle pattern, inner loop will iterate K times.

Java program to print triangle star pattern

package com.tcc.java.programs;

import java.util.*;

public class RightTrianglePattern {
    public static void main(String args[]) {
        int rows, i, j;
  
        Scanner in = new Scanner(System.in);
        System.out.println("Enter number of rows in pattern");
        rows = in.nextInt();

        for(i = 1; i <= rows; i++) {
            /* Prints one row of triangle */
            for(j = 1; j <= i; ++j) {
                System.out.print("* ");
            }
            /* move to next row */
            System.out.print("\n");
        }
    }
}
Output
Enter number of rows in pattern
6
* 
* * 
* * * 
* * * * 
* * * * * 
* * * * * *