Pascal triangle program in Java

In this post, you will learn different ways to print the Pascal triangle pattern using the Java programming language.

A Pascal triangle is a number pattern that reflects a triangle. Firstly, 1 is set at the top, and afterward, we begin placing the numbers in a three-sided design. The numbers that we get in each progression are the addition of the last two numbers. It is like the concept of triangular numbers. Each new number lies between two existing numbers and below them, and its value is the sum of the two numbers above it.

Algorithm to Print Pascal's Triangle in Java

1. Get an input value from the user or specify the value.
2. Use a forloop which ranges from 0 to n to print the rows.
3. Then use an inner forloop for j from 0 to (N – 1).
4. Print a single blank space "".
5. Then use an inner forloop for j from 0 to i to determine the value of the number inside the triangle.
6. Print the Pascal’s triangle according to the format.
7. Exit

Java program to print Pascal's Triangle

In the given Java program, we specify the number of rows up to which the Pascal triangle will be printed on the screen.

import java.io.*;
 
public class PascalTriangle {
    public int factorial(int i)
    {
        if (i == 0)
            return 1;
        return i * factorial(i - 1);
    }
    public static void main(String[] args)
    {
        int n = 8, i, j;
        PascalTriangle tri = new PascalTriangle();
        for (i = 0; i <= n; i++) {
            for (j = 0; j <= n - i; j++) {
 
                System.out.print(" ");
            }
            for (j = 0; j <= i; j++) {
 
                System.out.print(
                    " "
                    + tri.factorial(i)
                          / (tri.factorial(i - j)
                             * tri.factorial(j)));
            }
            System.out.println();
        }
    }
}

         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

Java program to print Pascal's Triangle of given size

In the given Java program, we ask the user to provide the number of rows up to which the Pascal triangle will be printed on the screen.

import java.util.Scanner;
import java.io.*;
 
public class PascalTriangle {
    public int factorial(int i)
    {
        if (i == 0)
            return 1;
        return i * factorial(i - 1);
    }
    public static void main(String[] args)
    {
        int i, j;
        Scanner s = new Scanner(System.in);
      
        System.out.print("Enter the Row Size of Pascal Triangle: ");
        int n = s.nextInt();
        PascalTriangle tri = new PascalTriangle();
        for (i = 0; i <= n; i++) {
            for (j = 0; j <= n - i; j++) {
 
                System.out.print(" ");
            }
            for (j = 0; j <= i; j++) {
 
                System.out.print(
                    " "
                    + tri.factorial(i)
                          / (tri.factorial(i - j)
                             * tri.factorial(j)));
            }
            System.out.println();
        }
    }
}

Enter the Row Size of Pascal Triangle:      11       
             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
    1 9 36 84 126 126 84 36 9 1
   1 10 45 120 210 252 210 120 45 10 1
  1 11 55 165 330 462 462 330 165 55 11 1

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