Pascal Triangle Example Java Program


Definition

Pascal's triangle is a triangular array of the binomial coefficients. The rows of Pascal's triangle (sequence A007318 in OEIS) are conventionally enumerated starting with row n = 0 at the top (the 0th row). The entries in each row are numbered from the left beginning with k = 0 and are usually staggered relative to the numbers in the adjacent rows. Having the indices of both rows and columns start at zero makes it possible to state that the binomial coefficient appears in the nth row and kth column of Pascal's triangle.

Pascal Triangle Example Program

import java.util.Scanner;
public class PascalTriangle {
    public static void main(String[] args) {
		Scanner in=new Scanner(System.in);
		System.out.println("Enter the number of rows");
		int numrows =in.nextInt();
		for(int i =0; i < numrows;i++){
			int num= 1;
			System.out.format("%"+(numrows-i)*2+"s","");
			for(int j=0;j <= i;j++) {
				System.out.format("%4d",num);
				num= num* (i - j) / (j + 1);
			}
			System.out.println(); 
		}
    }
}

Sample Output

Output is:
enter the number of rows
9
                     1
                   1   1
                 1   2   1
               1   3   3   1
             1   4   6   4   1
           1   5  10  10   5   1
         1   6  15  20  15   6   1
       1   7  21  35  35  21   7   1
     1   8  28  56  70  56  28   8   1