Pascal’s triangle java – Java Program to Print Hollow Right Pascal’s Triangle Star Pattern

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Program to Print Hollow Right Pascal’s Triangle Star Pattern

Pascal’s triangle java: In this article we are going to see how to print Hollow right pascal’s Tringle  star program.

Example-1

When row value=4
*
**
* *
*  *
* *
**
*
Example-2:

When row value=5
*
**
* *
*  *
*   *
*  *
* *
** 
*

Now, let’s see the actual program to print it.

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Approach:

  • Enter total row and store it in an integer variable row.
  • Take first outer for loop to print all rows of upper part .
    • Take  first inner for loop to print column values i.e., first inner for loop will print according to condition , i.e. if( c == 1 || c == r ) if condition satisfies then it will print star else it will print space.
  • Take second outer for loop for printing stars in creasing & decreasing order .
    • First inner for loop will print stars in decreasing order  with condition if( c == row-1 || c == r || r == row)
    • Second inner for loop will print stars in increasing condition .
  • Then go on printing the star symbol according to loop

JAVA Code:

Method-1 : Static Star Character

import java.util.*;
public class Main 
{    
    public static void main(String args[])   
    {   
     // taking variable for loop iteration and row .
    int row,r,c,d;
    //creating object 
    Scanner s = new Scanner(System.in);
    // entering the number of row
    System.out.print("Enter rows : ");
    row = s.nextInt();
    //outer for loop 
     for (r =1; r<=row; r++)
        {
            for ( c=1; c<=r; c++)
            {
                if( c == 1 || c == r )
                    System.out.print("*");
                else
                    System.out.print(" ");
            }
            System.out.println();
        }
        
        for ( r=1; r<=row-1; r++)
        {
            // Print star in decreasing order
            for ( c = row-1; c >= r; c--)
            {
                if( c == row-1 || c == r || r == row)
                    System.out.print("*");
                else
                    System.out.print(" ");
            }
            // Print space in increasing order
            for ( c = 1; c < r; c++)
            {
                System.out.print(" ");
            }
            
            System.out.println();
        }           
    }
}

Output :

 Enter Row: 5
*
**
* *
*  *
*   *
*  *
* *
** 
*

Method-2: User Input Character

import java.util.*;
public class Main 
{    
    public static void main(String args[])   
    {   
    // taking variable for loop iteration and row .
    int row,r,c,d;
    char random;
    //creating object 
    Scanner s = new Scanner(System.in);
    // entering the number of row
    System.out.print("Enter rows : ");
    row = s.nextInt();
    // entering the number of row
    System.out.print("Enter character : ");
    random = s.next().charAt(0);
    //outer for loop 
     for (r =1; r<=row; r++)
        {
            for ( c=1; c<=r; c++)
            {
                if( c == 1 || c == r )
                    System.out.print(random);
                else
                    System.out.print(" ");
            }
            System.out.println();
        }
        
        for ( r=1; r<=row-1; r++)
        {
            // Print star in decreasing order
            for ( c = row-1; c >= r; c--)
            {
                if( c == row-1 || c == r || r == row)
                    System.out.print(random);
                else
                    System.out.print(" ");
            }
            // Print space in increasing order
            for ( c = 1; c < r; c++)
            {
                System.out.print(" ");
            }
            
            System.out.println();
        }           
    }
}

Output :

 Enter Row: 5

Enter character : $
$
$$
$  $
$   $
$    $
$   $
$ $
$$ 
$

C Code:

#include <stdio.h>
int main() {
   int r, row, c ,d;
   printf("Enter rows: ");
   scanf("%d", &row);
     for (r =1; r<=row; r++)
        {
            for ( c=1; c<=r; c++)
            {
                if( c == 1 || c == r )
                    printf("*");
                else
                     printf(" ");
            }
            printf("\n");
        }
        for ( r=1; r<=row-1; r++)
        {
            // Print star in decreasing order
            for ( c = row-1; c >= r; c--)
            {
                if( c == row-1 || c == r || r == row)
                     printf("*");
                else
                    printf(" ");
            }
            // Print space in increasing order
            for ( c = 1; c < r; c++)
            {
                 printf(" ");
            }
             printf("\n");
        }           
   return 0;
}

Output :

 Enter Row: 5
*
**
* *
*  *
*   *
*  *
* *
** 
*

C++ Code:

#include <iostream>
using namespace std;
int main()
{
   int row, r , c ,d ;
   cout << "Enter  rows: ";
   cin >> row;
     for (r =1; r<=row; r++)
        {
            for ( c=1; c<=r; c++)
            {
                if( c == 1 || c == r )
                    cout <<"*";
                else
                    cout <<" ";
            }
            cout << "\n";
        }    
        for ( r=1; r<=row-1; r++)
        {
            // Print star in decreasing order
            for ( c = row-1; c >= r; c--)
            {
                if( c == row-1 || c == r || r == row)
                     cout <<"*";
                else
                     cout <<" ";
            }
            // Print space in increasing order
            for ( c = 1; c < r; c++)
            {
                cout <<" ";
            }
           cout << "\n";
        }               
   return 0;
}

Output :

 Enter Row: 5
*
**
* *
*  *
*   *
*  *
* *
** 
*

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