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

by

Program to Print Inverted Pascal’s Triangle Star Pattern

Pascal triangle java: In this article we are going to see how to print the triangle star program.

Example-1

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

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

Now, let’s see how program printing it.

Interested in programming and want to excel in it by choosing the short ways. Then, practicing with the available Java Program list is mandatory.

Approach:

  • Enter total row and store it in an integer variable row.
  • Take first for loop to print all rows.
  • Take first inner for loop to print column values i.e., first inner for loop will print all the spaces  in the column.
  • Take second inner for loop to print column values i.e., second inner for loop will print all the stars in the column.
  • 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();
    //counting space
    for (r=row;r>=1;r--)
        {
            //printing the spaces
            for(c=row-r;c>=1;c--)
                System.out.print(" ");
            //printing the stars
            for(c=1;c<=r;c++)
                 System.out.print(" * ");
            // taking to new line 
            System.out.println();
        }
}
}



Output:
Enter rows : 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;
    //creating object 
    Scanner s = new Scanner(System.in);
    // entering the number of row
    System.out.print("Enter rows : ");
    row = s.nextInt();
    
    // entering the symbol
    System.out.print("Enter symbol : ");
    char symbol = s.next().charAt(0); 
    
    //counting space
    for (r=row;r>=1;r--)
        {
            //printing the spaces
            for(c=row-r;c>=1;c--)
                System.out.print(" ");
            //printing the stars
            for(c=1;c<=r;c++)
                 System.out.print(" "+symbol+" ");
            // taking to new line 
            System.out.println();
        }
}
}



Output:

Enter rows : 5
Enter symbol : #
#  #  #  #  #
 #  #  #  #
  #  #  #
   #  #
    #

Explanation :

Iteration-1

r=5 (passes the first for loop condition) as it will iterate up to r>=1 times.

First inner for loop will iterate (row-r) to 1 that means , it  will print the space 0 time .

then 2nd inner for loop will iterate up to c<=r times so, it  prints the * 5 time .

So, star will be printed 5 time.

  * * * * *

Iteration-2

r=4 (passes the first for loop condition) as it will iterate up to r>=1 times.

First inner for loop will iterate (row-r) to 1 that means , it  will print the space 1  time .

then 2nd inner for loop will iterate up to c<=r times so, it  prints the * 4 time .

So, star will be printed 4 time.

  * * * *

Iteration-3

r=3 (passes the first for loop condition) as it will iterate up to r>=1 times.

First inner for loop will iterate (row-r) to 1 that means , it  will print the space 2  time .

then 2nd inner for loop will iterate up to c<=r times so, it  prints the * 3 time .

So, star will be printed 3 time.

   * * *

Iteration-4

r=2 (passes the first for loop condition) as it will iterate up to r>=1 times.

First inner for loop will iterate (row-r) to 1 that means , it  will print the space 3  time .

then 2nd inner for loop will iterate up to c<=r times so, it  prints the * 2 time .

So, star will be printed 2 time.

   * *

Iteration-5

r=1 (passes the first for loop condition) as it will iterate up to r>=1 times.

First inner for loop will iterate (row-r) to 1 that means , it  will print the space 4 time .

then 2nd inner for loop will iterate up to c<=r times so, it  prints the * 1 time .

So, star will be printed 1 time.

   *

Now when r=0, first for loop condition will fail so no other loops will be executed.

At last, we will see a pattern like this as output.

*  *  *  *  * 
 *  *  *  * 
  *  *  * 
   *  * 
    *

C Code:

#include <stdio.h>
int main() {
   int r, row, c ,d;
   printf("Enter rows: ");
   scanf("%d", &row);
    for (r=row;r>=1;r--)
        {
            for(c=row-r;c>=1;c--)
               printf(" ");
            for(c=1;c<=r;c++)
                 printf(" * ");
            printf("\n");
        }
   return 0;
}

Output:

Enter rows : 5
*  *  *  *  * 
 *  *  *  * 
  *  *  * 
   *  * 
    *

C++ Code:

#include <iostream>
using namespace std;
int main()
{
   int row, r , c ,d ;

   cout << "Enter  rows: ";
   cin >> row;
     for (r=row;r>=1;r--)
        {
            for(c=row-r;c>=1;c--)
               cout << " ";
            for(c=1;c<=r;c++)
                 cout << "* "; 
            cout << "\n";
        }
    return 0;

Output:

Enter rows : 5
*  *  *  *  * 
 *  *  *  * 
  *  *  * 
   *  * 
    *

Related Java Star Pattern Programs: