pascal triangle using array code example

Example 1: Pascal triangle in java using array

// Pascal triangle in java using array
import java.util.Scanner;
public class PascalTriangleUsingArray
{
   public static void main(String[] args)
   {
      Scanner sc = new Scanner(System.in);
      int num, a, b, arr[][], p;
      System.out.println("Please enter number of rows: ");
      num = sc.nextInt();
      p = num - 1;
      arr = new int[num][num];
      for(a = 0; a < num; a++)
      {
         for(b = 0; b <= a; b++)
            if(b == 0 || b == a)
               arr[a][b] = 1;
            else
               arr[a][b] = arr[a - 1][b - 1] + arr[a - 1][b];
      }
      System.out.println("Pascal's triangle: \n");
      for(a = 0; a < num; a++)
      {
         for(b = 0; b <= p; b++)
            System.out.print(" ");
         p--;
         for(b = 0; b <= a; b++)
            System.out.print(arr[a][b] + " ");
         System.out.println();
      }
      sc.close();
   }
}

Example 2: Pascal triangle program in java without using arrays

// Pascal triangle program in java without using arrays
import java.util.Scanner;
public class PascalTriangleDemo 
{
   public static void main(String[] args) 
   {
      System.out.println("Please enter number of rows to print pascal's triangle: ");
      Scanner sc = new Scanner(System.in);
      int row = sc.nextInt();            
      System.out.println("Pascal's triangle with " + row + " rows.");
      displayPascalTriangle(row);
      sc.close();
   }
   public static void displayPascalTriangle(int r) 
   {
      for(int a = 0; a < r; a++) 
      {
         int num = 1;
         System.out.printf("%" + (r - a) * 2 + "s", "");
         for(int b = 0; b <= a; b++) 
         {
            System.out.printf("%4d", num);
            num = num * (a - b) / (b + 1);
         }
         System.out.println();
      }
   }
}