Java Program to Print Hollow Mirrored Right Triangle Star Pattern

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Program to Print Hollow Mirrored Right Triangle Star Pattern

In this article we are going to see how to print the Hollow and Mirrored Right Angle Star Pattern

Example-1

For rows = 5
      *
     **
   *  *
 *    *
*****
Example-2

For rows = 6
         *
       **
     *  *
   *    *
 *      *
******

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 rows.
  • Take one outer for loop to iterate the rows.
  • Take two inner for loops, one to print the space and the other one to print the star.
  • After every iteration print a new line.

JAVA Code:

Method-1 : Static Star Character

import java.util.Scanner;
class Main
{
    public static void main(String[] args)  
    {  
        Scanner scan = new Scanner(System.in);
        System.out.print("Rows : ");
        //Taking input from user
        int  rows=scan.nextInt();
        //Outer loop
        for (int r=1; r<=rows; r++)
        {//Inner loop
            // Print space in decreasing order
            for (int c=rows; c>r; c--)
            {
                System.out.print(" ");
            }
            // Print stars in increasing order
            for (int k=1; k<=r; k++)
            {
                if( k == 1 || k == r || r == rows)
                    System.out.print("*");
                else
                    System.out.print(" ");
            }
            //Prints a newline
            System.out.println();
        }  
    }  
}



Output:

Rows : 5
     *
   * *
  *  *
 *   *
*****

Method-2 : User Input Character

import java.util.Scanner;
class Main
{
    public static void main(String[] args)  
    {  
        Scanner scan = new Scanner(System.in);
        System.out.print("Rows : ");
        //Taking rows input from user
        int  rows=scan.nextInt();
        System.out.print("Symbol : ");
        //Taking symbol input from user
        char s=scan.next().charAt(0);
        
        //Outer loop
        for (int r=1; r<=rows; r++)
        {//Inner loop
            // Print space in decreasing order
            for (int c=rows; c>r; c--)
            {
                System.out.print(" ");
            }
            // Print stars in increasing order
            for (int k=1; k<=r; k++)
            {
                if( k == 1 || k == r || r == rows)
                    System.out.print(s);
                else
                    System.out.print(" ");
            }
            //Prints a newline
            System.out.println();
        }  
    }  
}



Output:

Rows : 5
Symbol : $
        $
     $ $
   $   $
  $    $
$$$$$

Explanation :

Let’s understand the program by going through the detailed explanation.

We have taken rows value as 5.

Iteration-1

r=1, goes in the first inner loop and prints four space as c > r.

It prints 1 star as k == 1

    *

Iteration-2

r=2, goes in the first inner loop and prints three space as c > r.

It prints two star as k == 1 and k == r

   **

Iteration-3

r=3, goes in the first inner loop and prints two space as c > r.

It prints two stars as k ==1 and k == r and rest space.

  *  *

Iteration-4

r=4, goes in the first inner loop and prints one space as c > r.

It prints two stars as k == 1 and k == r and rest space.

 *    *

Iteration-5

r=5, goes out the first inner loop. For the next loop it prints 5 stars as r == rows

*****

After this r=6 i.e.  so program will come out of the loop.

Now, after end of all iteration we will see the complete pattern is printed on the output screen like this.

     *
    **
  *  *
 *   *
*****

C Code:

#include <stdio.h>
int main(int argc, char const *argv[])
{
    printf("Enter rows : ");
    int rows;
    //Taking row as input from user
    scanf("%d", &rows);
    //Outer loop
    for (int r = 1; r <= rows; r++)
    { //Inner loop
        // Print space in decreasing order
        for (int c = rows; c > r; c--)
        {
            printf(" ");
        } //Inner loop 2
        // Print stars in increasing order
        for (int k = 1; k <= r; k++)
        {
            if (k == 1 || k == r || r == rows)
            {
                printf("*");
            }
            else
            {
                printf(" ");
            }
        } //To print a newline
        printf("\n");
    }
    return 0;
}


Output:

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

C++ Code:

#include <iostream>
using namespace std;
int main(int argc, char const *argv[])
{
    cout << "Enter rows : ";
    int rows;
    //Taking row as input from user
    cin >> rows;
    //Outer loop
    for (int r = 1; r <= rows; r++)
    { //Inner loop
        // Print space in decreasing order
        for (int c = rows; c > r; c--)
        {
            cout << " ";
        }
        // Print stars in increasing order
        for (int k = 1; k <= r; k++)
        {
            if (k == 1 || k == r || r == rows)
                cout << "*";
            else
                cout << " ";
        } //To print a newline
        cout << endl;
    }
    return 0;
}

Output:

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

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