Pascal's triangle 2d array - formatting printed output

Question

I have a small assignment where I have to use a 2d array to produce Pascal\'s triangle. Here is my code, and it works. there is an extra credit opportunity if I display the

Answer 1

Here I had modified your code, it prints wonderfully for ROW size till 13, coz of the limitation of my console window.

import java.util.*; 

public class Pascal { 
    public static final int ROW = 12;
    private static int max = 0;

    public static void main(String[] args) { 
        int[][] pascal  = new int[ROW +1][];
        pascal[1] = new int[1 + 2];
        pascal[1][1] = 1;
        for (int i = 2; i <= ROW; i++) {
            pascal[i] = new int[i + 2];
            for (int j = 1; j < pascal[i].length - 1; j++) {
                pascal[i][j] = pascal[i-1][j-1] + pascal[i-1][j];
                String str = Integer.toString(pascal[i][j]);
                int len = str.length();
                if (len > max)
                    max = len;
            }
        }


        for (int i = 1; i <= ROW; i++) {                
            for (int k = ROW; k > i; k--)
                System.out.format("%-" + max + "s", " ");
            for (int j = 1; j < pascal[i].length - 1; j++)                      
                System.out.format("%-" + (max + max) + "s",  pascal[i][j]);
            System.out.println();
        }
    }
}

Hopefully this might help.

Regards

Answer 2

You're encountering spacing issues because you need to add whitespace to certain numbers to accommodate space that larger numbers occupy. First determine what the largest number you plan to print is (programmatically). Then determine the number of digits in that number log(n). You can then use this number to print whitespace for numbers that have less digits than your largest number to make your printing look nicer.