Java program to display pascal triangle

Let’s learn java program to display pascal triangle.

Java program to display pascal triangle

Pascal triangle is a triangle of binomial coefficients arranged in the form of a triangle. It is named after french mathematician Blaise Pascal. Pascal triangle looks like this,

    1    
   1 1   
  1 2 1  
 1 3 3 1 
1 4 6 4 1

In the above triangle there are five rows. First row starts with digit 1. Then each digit in a row is the sum of left digit and right digit of above row. Suppose, if a digit is missing in the above row, it is assumed as 0.

NOTE:

  • diagonals adjacent to the border diagonals contain natural numbers in an order.
  • sum of numbers in each row is twice the sum of numbers in above row.

Binomial coefficient can be calculated using formula,

C(n,r) = n!/((n-r)!*r!)

Time complexity: O(n²) where n is number of lines.

Here’s the java program to print pascal triangle,

import java.util.Scanner;

public class PascalsTriangleJava 
{
   public static void main(String[] args) 
   {
      System.out.println("Please enter number of rows : ");
      Scanner sc = new Scanner(System.in);
      int num = sc.nextInt();
      int row = num;
      int number = 1; 
 
      for(int i = 0; i < num; i++)
      {
         for(int r = 1; r <= row; r++)
         {
            System.out.print(" ");
         }
         number = 1;
         for(int j = 0; j <= i; j++)
         {
            System.out.print(number + " ");
            number = number * (i - j) / (j + 1); 
         }
         row--;
         System.out.println();
         sc.close();
      }
   }
}



Output:

java program to display pascal triangle

Also read – garbage collection in java