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Hollow lower triangular pattern

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Given the value of n, i.e, the number of rows/columns for a square, print the pattern.
Examples : 
 

Input : n = 8
Output :
 * * * * * * * *
 * * * * * * * *
 *   * * * * * *
 *     * * * * *
 *       * * * *
 *         * * *
 *           * *
 * * * * * * * *

Input : n = 15
Output :
 * * * * * * * * * * * * * * *
 * * * * * * * * * * * * * * *
 *   * * * * * * * * * * * * *
 *     * * * * * * * * * * * *
 *       * * * * * * * * * * *
 *         * * * * * * * * * *
 *           * * * * * * * * *
 *             * * * * * * * *
 *               * * * * * * *
 *                 * * * * * *
 *                   * * * * *
 *                     * * * *
 *                       * * *
 *                         * *
 * * * * * * * * * * * * * * *

 

Below is the implementation to print hollow lower triangular pattern : 
 

C++




// C++ implementation of hollow
// lower triangular pattern
#include <bits/stdc++.h>
using namespace std;
  
// function to print the pattern
void print_pattern(int n)
{
    int k = 1;
  
    // for loop to keep track of
    // number of rows
    for (int i = 1; i <= n; i++) {
  
        // for loop to keep track of
        // number of columns
        for (int j = 1; j <= n; j++) {
  
            // if last row or first column
            if (i == n || j == 1)
                cout << " "
                     << "*";
  
            // to skip the lower triangular part
            else if (j < k)
                cout << " "
                     << " ";
  
            // to print star in remaining portion
            else
                cout << " "
                     << "*";
        }
        cout << endl;
        k++;
    }
}
  
// driver code
int main()
{
    int n = 8;
    print_pattern(n);
    return 0;
}


Java




// Java implementation of hollow
// lower triangular pattern
import java.io.*;
  
class GFG {
  
    // function to print the pattern
    static void print_pattern(int n)
    {
          
        int k = 1;
  
        // for loop to keep track of
        // number of rows
        for (int i = 1; i <= n; i++) {
  
            // for loop to keep track of
            // number of columns
            for (int j = 1; j <= n; j++) {
  
                // if last row or first column
                if (i == n || j == 1)
                    System.out.print(" "
                                    + "*");
  
                // to skip the lower triangular 
                // part
                else if (j < k)
                    System.out.print(" "
                                    + " ");
  
                // to print star in remaining
                // portion
                else
                    System.out.print(" "
                                    + "*");
            }
            System.out.println();
            k++;
        }
    }
  
    // driver code
    public static void main(String[] args)
    {
        int n = 8;
          
        print_pattern(n);
    }
}
  
// This code is contributed by vt_m


Python3




# Python3 implementation of hollow
# lower triangular pattern
  
# Function to print the pattern
def print_pattern(n):
    k = 1;
  
    # for loop to keep track 
    # of number of rows
    for i in range(1, n + 1):
          
        # for loop to keep track
        # of number of columns
        for j in range(1, n + 1): 
              
            # if last row or 
            # first column
            if (i == n or j == 1):
                print(" *", end = "");
  
            # to skip the lower 
            # triangular part
            elif (j < k):
                print(" ", end = " ");
  
            # to print star in 
            # remaining portion
            else:
                print(" *", end = "");
        print();
        k += 1;
  
# Driver code
n = 8;
print_pattern(n);
  
# This code is contributed 
# by Mithun Kumar


C#




// implementation of hollow
// lower triangular pattern
using System;
  
class GFG {
  
    // function to print the pattern
    static void print_pattern(int n)
    {
  
        int k = 1;
  
        // for loop to keep track of
        // number of rows
        for (int i = 1; i <= n; i++) {
  
            // for loop to keep track of
            // number of columns
            for (int j = 1; j <= n; j++) {
  
                // if last row or first column
                if (i == n || j == 1)
                    Console.Write(" "
                                  + "*");
  
                // to skip the lower triangular
                // part
                else if (j < k)
                    Console.Write(" "
                                  + " ");
  
                // to print star in remaining
                // portion
                else
                    Console.Write(" "
                                  + "*");
            }
            Console.WriteLine();
            k++;
        }
    }
  
    // driver code
    public static void Main()
    {
        int n = 8;
  
        print_pattern(n);
    }
}
  
// This code is contributed by vt_m


PHP




<?php
// PHP implementation of hollow
// lower triangular pattern
  
// Function to print the pattern
function print_pattern($n)
{
    $k = 1;
  
    // for loop to keep track of
    // number of rows
    for ($i = 1; $i <= $n; $i++) 
    {
  
        // for loop to keep track of
        // number of columns
        for ($j= 1; $j<= $n; $j++) 
        {
  
            // if last row or 
            // first column
            if ($i == $n || $j== 1)
                echo " *";
  
            // to skip the lower 
            // triangular part
            else if ($j < $k)
                echo "  ";
  
            // to print star in 
            // remaining portion
            else
                echo " *";
        }
        echo "\n";
        $k++;
    }
}
  
// Driver code
$n = 8;
print_pattern($n);
  
// This code is contributed by Mithun Kumar
?>


Javascript




<script>
      // JavaScript implementation of hollow
      // lower triangular pattern
  
      // function to print the pattern
      function print_pattern(n) {
        var k = 1;
  
        // for loop to keep track of
        // number of rows
        for (var i = 1; i <= n; i++) 
        {
          
          // for loop to keep track of
          // number of columns
          for (var j = 1; j <= n; j++)
          {
            
            // if last row or first column
            if (i == n || j == 1) document.write("  " + "*");
              
            // to skip the lower triangular part
            else if (j < k) document.write("  " + "  ");
              
            // to print star in remaining portion
            else document.write("  " + "*");
          }
          document.write("<br>");
          k++;
        }
      }
  
      // driver code
      var n = 8;
      print_pattern(n);
        
      // This code is contributed by rdtank.
    </script>


Output : 
 

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

Time Complexity : O(n2) ,where n is number of rows in the pattern.

Auxiliary Space : O(1) ,as we are not using any extra space.

 



Last Updated : 20 Feb, 2023
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