Make triangle with '*' & print number (School :()

[Seldimi]

Hello all...
I am new to these forums and i need some help regarding java for the university... Here are 2 things i have to make as java classes but i dont know how:

1st) Print triagle : Read a positive number posted by user N (N>=3) and print a triangle with asterisks that will be N lines (see example)
(eg N=4)

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

Its something with loop but i dunno what

2nd) Print number: Read a user submited number from 0 to 99999 and post the ammount of the digits of the number submited. Next print same number (the one submited) in a 5 fields format Eg number 13, digits=2 and print as 00013

If you help me in both i take a good grade for current lab and i will be very happy for it

Hope i get replies

[aniseed]

Hint for the first, run the loop from 1 to N and print 2N -1 asterisks on each line.

[Seldimi]

hhMMM im new to java (i only used php in the past) so can u be more explainable?
I just dont know what to print and how it print (println or print) in the loop

[Seldimi]

I found the solution for 2nd code, its the following :

					System.out.print("Input number R:");
					int R = Integer.parseInt(br.readLine());	
					while (R<0 || R>99999) {
						System.out.println("Error. Wrong Input. Try Again");
						System.out.print("Input number R:");
						R = Integer.parseInt(br.readLine());
					System.out.print("The digit number is :");
					}
					int countzero = 0; // Apothikeusi Midenikwn Stixeiwn
					if (R<10) {
						System.out.println("1 Digit");
						countzero = 4;
					} else if (R<100) {
						System.out.println("2 Digits");
						countzero = 3;
					} else if (R<1000) {
						System.out.println("3 Digits");
						countzero = 2;
					} else if (R<10000) {
						System.out.println("4 Digits");
						countzero = 1;
					} else if (R<100000) {
						System.out.println("5 Digits");
						countzero = 0;
					}
					for (int g=0; g<countzero; g++)
						System.out.print("0");
					System.out.println(R);

I must make the tree only now

[prometheuzz]

for(int i = 1; i <= n; i++) { // n is the number of lines

  int numOfSpaces = /* ? */;
  int numOfAsterisks = /* ? */;
            
  for(int j = 1; j <= numOfSpaces; j++) 
    System.out.print(' ');
            
  for(int j = 1; j <= numOfAsterisks; j++)
    System.out.print('*');
            
  System.out.print('\n');
}

Try to finish it now. If you don't see it immediatelly, write down on paper the number of spaces and asterixes for each line. Try to see how those number relate to i.

[ftr]

Ok, here's how I did the code for the triangle

import java.util.*;
import javax.swing.JOptionPane;

public class pyramid{
	public static void main (String[]Args){
		
		int input = 0;
		String temp_string = JOptionPane.showInputDialog("Please enter an integer");
		temp_string = temp_string.trim();
		input= Integer.parseInt(temp_string);
		
		for (int i=1; i<=input; i++)
		{
			for (int j=1; j<=i; j++)
			{
				System.out.print("*");
			}
			System.out.println("");
		}
	}
}

This just gets you an output like

*
**
***

as opoosed to being lined up like you said

[Seldimi]

Thank you a lot, i really appreciated ur help

[W3N]

import javax.swing.JOptionPane;

public class TriangleWithAsterisk {

    public static void main(String[] args)
    {
        int n;
        
        n = Integer.valueOf(JOptionPane.showInputDialog(null, "Enter the number of lines --> "));
        
        for (int i = 0; i < n; i++)
        {
            int stars = 1 + 2 * (i);
            int space = n - i;
            for (int j = 0; j < space; j++)
            {
                System.out.print("  ");
            }
            
            for (int k = 0; k < stars; k++)
            {
                System.out.print("* ");
            }
            System.out.println();
        }
        
    }
}


i got an output like this when i entered 6

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

[Seldimi]

Geeeeeeeeee thanx a lot
Really aprreciated your help!