Java Program to Print Triangle Numbers Pattern

Write a Java program to print triangle numbers pattern using for loop.

package Shapes3;

import java.util.Scanner;

public class TriangleNum1 {

	private static Scanner sc;
	
	public static void main(String[] args) {
		sc = new Scanner(System.in);
		
		System.out.print("Enter Triangle Number Pattern Rows = ");
		int rows = sc.nextInt();
		
		System.out.println("Printing Triangle Number Pattern");
		
		for (int i = 1; i <= rows; i++ ) 
		{
			for (int j = rows; j > i; j-- ) 
			{
				System.out.print(" ");
			}
			for(int k = 1; k <= i; k++) 
			{
				System.out.print(k + " ");
			}
			System.out.println();
		}
	}
}
Java Program to Print Triangle Numbers Pattern

This Java program prints the triangle pattern of numbers using a while loop.

package Shapes3;

import java.util.Scanner;

public class TriangleNum2 {

	private static Scanner sc;
	
	public static void main(String[] args) {
		sc = new Scanner(System.in);
		
		System.out.print("Enter Triangle Number Pattern Rows = ");
		int rows = sc.nextInt();
		
		System.out.println("Printing Triangle Number Pattern");
		int j, k, i = 1;
		
		while( i <= rows ) 
		{
			j = rows;
			while(j > i ) 
			{
				System.out.print(" ");
				j--;
			}
			
			k = 1;
			while(k <= i) 
			{
				System.out.print(k + " ");
				k++;
			}
			System.out.println();
			i++;
		}
	}
}
Enter Triangle Number Pattern Rows = 8
Printing Triangle Number Pattern
       1 
      1 2 
     1 2 3 
    1 2 3 4 
   1 2 3 4 5 
  1 2 3 4 5 6 
 1 2 3 4 5 6 7 
1 2 3 4 5 6 7 8 

This example uses the do while loop to display the triangle of numbers pattern.

package Shapes3;

import java.util.Scanner;

public class TriangleNum3 {

	private static Scanner sc;
	
	public static void main(String[] args) {
		sc = new Scanner(System.in);
		
		System.out.print("Enter Rows = ");
		int rows = sc.nextInt();
		
		System.out.println("");
		int j, k, i = 1;
		
		do 
		{
			j = rows;
			do 
			{
				System.out.print(" ");

			} while(j-- > i );
			
			k = 1;
			do
			{
				System.out.print(k + " ");
	
			} while(++k <= i);
			System.out.println();

		} while(++i <= rows );
	}
}
Enter Rows = 9

         1 
        1 2 
       1 2 3 
      1 2 3 4 
     1 2 3 4 5 
    1 2 3 4 5 6 
   1 2 3 4 5 6 7 
  1 2 3 4 5 6 7 8 
 1 2 3 4 5 6 7 8 9 

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Suresh is the founder of TutorialGateway and a freelance software developer. He specialized in Designing and Developing Windows and Web applications. The experience he gained in Programming and BI integration, and reporting tools translates into this blog. You can find him on Facebook or Twitter.