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Program to print the pattern with two hollow Triangles
  • Last Updated : 21 Apr, 2021

Given a number n, the task is to write a program to draw the following pattern using ‘$’.
 

         $
       $ $ $
     $ $ $ $ $
   $ $ $ $ $ $ $
   $           $
   $ $       $ $
   $ $ $   $ $ $
   $ $ $ $ $ $ $
   $ $ $   $ $ $
   $ $       $ $
   $           $
   $ $ $ $ $ $ $
     $ $ $ $ $
       $ $ $
         $

 

Approach: 
The above pattern is printed by breaking it into smaller patterns: 
 

  1. The above triangle 
     
        $
      $ $ $
    $ $ $ $ $
  $ $ $ $ $ $ $
  1. This is done with the help of for loop for rows 0 to n-1. Firstly the space is printed, then the ‘$’ is printed. 
     
  2. The middle body 
     
   $           $
   $ $       $ $
   $ $ $   $ $ $
   $ $ $ $ $ $ $
   $ $ $   $ $ $
   $ $       $ $
   $           $
  1. This again is divided into 3 smaller patterns: 
    • The upper middle body 
       
   $           $
   $ $       $ $
   $ $ $   $ $ $
  • This is done with the help of for loop for rows 0 to n-2. Firstly the left ‘$’ is printed, then the space is printed, then the right ‘$’ is printed. 
     
  • The middle middle body 
     
   $ $ $ $ $ $ $
  • This is done with the help of for loop for row = n-1. Here only the ‘$’ is printed for i 0 to (2n -1). 
     
  • The lower middle body 
     
   $ $ $   $ $ $
   $ $       $ $
   $           $
  • This is done with the help of for loop for rows n to 2n-1. Firstly the left ‘$’ is printed, then the space is printed, then the right ‘$’ is printed. 
     
  1. The lower triangle 
     
   $ $ $ $ $ $ $
     $ $ $ $ $
       $ $ $
         $
  1. This is done with the help of for loop for rows 0 to n-1. This is done similar to the upper triangle pattern. 
     

Hence the complete pattern will be drawn.
Below program prints the pattern as shown above: 
 

C++




// C++ implementation of above approach
 
#include <iostream>
 
using namespace std;
 
void printPattern(int n)
    {
    // for upper triangle
  //     $
 //    $ $ $
 //  $ $ $ $ $
// $ $ $ $ $ $ $
 
        for (int r = 0; r < n; r++) {
 
            // for space
            for (int i = r; i < n - 1; i++) {
                cout << " " ;
                cout << " " ;
                         }
 
            // for $
            for (int i = 0; i < 2 * r + 1; i++)
                cout << "$ " ;
 
            // new line
                cout << endl ;
        }
 
        // for middle body
        // $           $
        // $ $       $ $
        // $ $ $   $ $ $
        // $ $ $ $ $ $ $
        // $ $ $   $ $ $
        // $ $       $ $
        // $           $
        for (int r = 0; r < 2 * n - 1; r++) {
            if (r < n - 1) {
 
                // for body
                // $           $
                // $ $       $ $
                // $ $ $   $ $ $
 
 
                // for $
                for (int i = 0; i <= r; i++)
                    cout << "$ " ;
 
                // for space
                for (int i = 0; i <= 2 * (n - r - 1)-2; i++) {
                   cout << " " ;
                    cout << " " ;
                     
                }
 
                // for $
                for (int i = 0; i <= r; i++)
                    cout << "$ " ;
            }
            else if (r == n - 1) {
 
                // for body
                // $ $ $ $ $ $ $
 
                // for $
                for (int i = 0; i < 2 * r + 1; i++)
                    cout << "$ " ;
            }
            else {
 
                // for body
                // $ $ $   $ $ $
                // $ $       $ $
                // $           $
 
                // for $
                for (int i = 2 * n - 1; i > r; i--)
                    cout << "$ " ;
 
                // for space
                for (int i = n; i <= r; i++) {
                    cout << " " ;
                    cout << " " ;
                     
                }
 
                // for space
                for (int i = n; i < r; i++) {
                    cout << " " ;
                    cout << " " ;
                     
                }
 
                // for $
                for (int i = 2 * n - 1; i > r; i--)
                    cout << "$ " ;
            }
 
            // new line
            cout << endl ;
        }
 
        // for lower triangle
        // $ $ $ $ $ $ $
        //   $ $ $ $ $
        //     $ $ $
        //       $
 
        for (int r = 0; r < n; r++) {
 
            // for space
            for (int i = 0; i < r; i++){
                cout << " " ;
                cout << " " ;
                }
 
            // for $
            for (int i = 0; i < 2 * (n - r) - 1; i++)
                cout << "$ " ;
 
            // new line
                cout << endl ;
        }
    }
 
 
int main()
{
     
    int n = 4;
    printPattern(n);
    return 0;
     
    // This code is contributed by ANKITRAI1
}

Java




// Java implementation of above approach
public class GFG {
 
    public static void printPattern(int n)
    {
    // for upper triangle
  //     $
 //    $ $ $
 //  $ $ $ $ $
// $ $ $ $ $ $ $
 
        for (int r = 0; r < n; r++) {
 
            // for space
            for (int i = r; i < n - 1; i++){
                System.out.print(" ");
                System.out.print(" ");
            }
 
            // for $
            for (int i = 0; i < 2 * r + 1; i++)
                System.out.print("$ ");
 
            // new line
            System.out.println();
        }
 
        // for middle body
        // $           $
        // $ $       $ $
        // $ $ $   $ $ $
        // $ $ $ $ $ $ $
        // $ $ $   $ $ $
        // $ $       $ $
        // $           $
 
        for (int r = 0; r < 2 * n - 1; r++) {
            if (r < n - 1) {
 
                // for body
                // $           $
                // $ $       $ $
                // $ $ $   $ $ $
 
                // for $
                for (int i = 0; i <= r; i++)
                    System.out.print("$ ");
 
                // for space
                for (int i = 0; i <= 2 * (n - r - 1) - 2; i++){
                    System.out.print(" ");
                    System.out.print(" ");
                }
 
                // for $
                for (int i = 0; i <= r; i++)
                    System.out.print("$ ");
            }
            else if (r == n - 1) {
 
                // for body
                // $ $ $ $ $ $ $
 
                // for $
                for (int i = 0; i < 2 * r + 1; i++)
                    System.out.print("$ ");
            }
            else {
 
                // for body
                // $ $ $   $ $ $
                // $ $       $ $
                // $           $
 
                // for $
                for (int i = 2 * n - 1; i > r; i--)
                    System.out.print("$ ");
 
                // for space
                for (int i = n; i <= r; i++){
                    System.out.print(" ");
                    System.out.print(" ");
                }
 
                // for space
                for (int i = n; i < r; i++){
                    System.out.print(" ");
                    System.out.print(" ");
                }
 
                // for $
                for (int i = 2 * n - 1; i > r; i--)
                    System.out.print("$ ");
            }
 
            // new line
            System.out.println();
        }
 
        // for lower triangle
        // $ $ $ $ $ $ $
        //   $ $ $ $ $
        //     $ $ $
        //       $
 
        for (int r = 0; r < n; r++) {
 
            // for space
            for (int i = 0; i < r; i++){
                System.out.print(" ");
                System.out.print(" ");
            }
 
            // for $
            for (int i = 0; i < 2 * (n - r) - 1; i++)
                System.out.print("$ ");
 
            // new line
            System.out.println();
        }
    }
 
    // Driver Code
    public static void main(String[] args)
    {
 
        int n = 4;
        printPattern(n);
    }
}

Python3




# Python 3 implementation of above approach
 
def printPattern(n):
    # for upper triangle
#     $
# $ $ $
# $ $ $ $ $
# $ $ $ $ $ $ $
 
        for r in range(0,n,1):
            # for space
            for i in range(r,n - 1,1):
                print(" ",end = " ")
 
            # for $
            for i in range(0,2 * r + 1,1):
                print("$",end = " ")
 
            # new line
            print("\n")
         
        # for middle body
        # $         $
        # $ $     $ $
        # $ $ $ $ $ $
        # $ $ $ $ $ $ $
        # $ $ $ $ $ $
        # $ $     $ $
        # $         $
        for r in range(0,2 * n - 1,1):
            if (r < n - 1):
                # for body
                # $         $
                # $ $     $ $
                # $ $ $ $ $ $
 
 
                # for $
                for i in range(0,r+1,1):
                    print("$",end = " ")
 
                # for space
                for i in range(0,2 * (n - r - 1)-2+1,1):
                    print(" ",end = " ")
                             
                # for $
                for i in range(0,r+1,1):
                    print("$", end = " ")
            elif (r == n - 1):
                # for body
                # $ $ $ $ $ $ $
 
                # for $
                for i in range(0,2 * r + 1,1):
                    print("$",end = " ")
             
            else:
                # for body
                # $ $ $ $ $ $
                # $ $     $ $
                # $         $
 
                # for $
                i = 2 * n - 1
                while(i > r):
                    print("$",end = " ")
                    i -= 1
 
                # for space
                for i in range(n,r+1,1):
                    print(" ",end = " ")            
                 
                # for space
                for i in range(n,r,1):
                    print(" ",end = " ")
         
                 
                # for $
                i = 2 * n - 1
                while(i > r):
                    print("$",end = " ")
                    i -=1
 
            # new line
            print("\n")
        # for lower triangle
        # $ $ $ $ $ $ $
        # $ $ $ $ $
        #     $ $ $
        #     $
 
        for r in range(0,n,1):
            # for space
            for i in range(0,r,1):
                print(" ",end = " ")
 
            # for $
            for i in range(0,2 * (n - r) - 1,1):
                print("$",end = " ")
 
            # new line
            print("\n")
# driver code
if __name__ == '__main__':
    n = 4
    printPattern(n)
     
# This code is contributed by
# Surendra_Gangwar
    

C#




// C# implementation of above approach
using System;
 
class GFG {
 
    public static void printPattern(int n) {
         
        // for upper triangle
        //     $
        //    $ $ $
        //  $ $ $ $ $
        // $ $ $ $ $ $ $
        for (int r = 0; r < n; r++) {
 
            // for space
            for (int i = r; i < n - 1; i++) {
                Console.Write(" ");
                Console.Write(" ");
            }
 
            // for $
            for (int i = 0; i < 2 * r + 1; i++)
            Console.Write("$ ");
 
            // new line
            Console.Write("\n");
        }
 
        // for middle body
        // $           $
        // $ $       $ $
        // $ $ $   $ $ $
        // $ $ $ $ $ $ $
        // $ $ $   $ $ $
        // $ $       $ $
        // $           $
 
        for (int r = 0; r < 2 * n - 1; r++) {
            if (r < n - 1) {
 
                // for body
                // $           $
                // $ $       $ $
                // $ $ $   $ $ $
 
                // for $
                for (int i = 0; i <= r; i++)
                Console.Write("$ ");
 
                // for space
                for (int i = 0; i <= 2 * (n - r - 1) - 2; i++) {
                    Console.Write(" ");
                    Console.Write(" ");
                }
 
                // for $
                for (int i = 0; i <= r; i++)
                Console.Write("$ ");
            }
            else if (r == n - 1) {
 
                // for body
                // $ $ $ $ $ $ $
 
                // for $
                for (int i = 0; i < 2 * r + 1; i++)
                Console.Write("$ ");
            }
            else {
 
                // for body
                // $ $ $   $ $ $
                // $ $       $ $
                // $           $
 
                // for $
                for (int i = 2 * n - 1; i > r; i--)
                Console.Write("$ ");
 
                // for space
                for (int i = n; i <= r; i++) {
                    Console.Write(" ");
                    Console.Write(" ");
                }
 
                // for space
                for (int i = n; i < r; i++) {
                    Console.Write(" ");
                    Console.Write(" ");
                }
 
                // for $
                for (int i = 2 * n - 1; i > r; i--)
                Console.Write("$ ");
            }
 
            // new line
            Console.Write("\n");
        }
 
        // for lower triangle
        // $ $ $ $ $ $ $
        //   $ $ $ $ $
        //     $ $ $
        //       $
 
        for (int r = 0; r < n; r++) {
 
            // for space
            for (int i = 0; i < r; i++) {
                Console.Write(" ");
                Console.Write(" ");
            }
 
            // for $
            for (int i = 0; i < 2 * (n - r) - 1; i++)
            Console.Write("$ ");
 
            // new line
            Console.Write("\n");
        }
    }
 
    // Driver Code
    public static void Main() {
 
        int n = 4;
        printPattern(n);
    }
}
 
// This code is contributed by ChitraNayal

PHP




<?php
// PHP implementation of above approach
 
function printPattern($n)
{
    // for upper triangle
    // $
    // $ $ $
    // $ $ $ $ $
    // $ $ $ $ $ $ $
    for ($r = 0; $r < $n; $r++)
    {
 
        // for space
        for ($i = $r; $i < $n - 1; $i++)
        {
            echo (" ") ;
            echo (" ") ;
        }
 
        // for $
        for ($i = 0; $i < 2 * $r + 1; $i++)
            echo ("$ ") ;
 
        // new line
        echo ("\n") ;
    }
 
    // for middle body
    // $         $
    // $ $ $ $
    // $ $ $ $ $ $
    // $ $ $ $ $ $ $
    // $ $ $ $ $ $
    // $ $ $ $
    // $         $
    for ($r = 0; $r < 2 * $n - 1; $r++)
    {
        if ($r < $n - 1)
        {
 
            // for body
            // $         $
            // $ $ $ $
            // $ $ $ $ $ $
 
            // for $
            for ($i = 0; $i <= $r; $i++)
                echo("$ ") ;
 
            // for space
            for ($i = 0;
                 $i <= 2 * ($n - $r - 1) - 2;
                 $i++)
            {
                echo (" ");
                echo (" ");
                 
            }
 
            // for $
            for ($i = 0; $i <= $r; $i++)
                echo("$ ");
        }
        else if ($r == $n - 1)
        {
 
            // for body
            // $ $ $ $ $ $ $
 
            // for $
            for ($i = 0; $i < 2 * $r + 1; $i++)
                echo("$ ") ;
        }
        else
        {
 
            // for body
            // $ $ $ $ $ $
            // $ $ $ $
            // $         $
 
            // for $
            for ($i = 2 * $n - 1; $i > $r; $i--)
                echo("$ ") ;
 
            // for space
            for ($i = $n; $i <= $r; $i++)
            {
                echo(" ") ;
                echo(" ") ;
            }
 
            // for space
            for ($i = $n; $i < $r; $i++)
            {
                echo (" ") ;
                echo (" ") ;
            }
 
            // for $
            for ($i = 2 * $n - 1; $i > $r; $i--)
                echo("$ ") ;
        }
 
        // new line
        echo("\n") ;
    }
 
    // for lower triangle
    // $ $ $ $ $ $ $
    // $ $ $ $ $
    // $ $ $
    // $
    for ($r = 0; $r < $n; $r++)
    {
 
        // for space
        for ($i = 0; $i < $r; $i++)
        {
            echo(" ") ;
            echo(" ") ;
        }
 
        // for $
        for ($i = 0; $i < 2 * ($n - $r) - 1; $i++)
            echo ("$ ") ;
 
        // new line
        echo ("\n") ;
    }
}
 
// Driver Code
$n = 4;
printPattern($n);
 
 
// This code is contributed
// by Shivi_Aggarwal
?>

Javascript




<script>
      // JavaScript implementation of above approach
      function printPattern(n)
      {
       
        // for upper triangle
        //       $
        //     $ $ $
        //   $ $ $ $ $
        // $ $ $ $ $ $ $
 
        for (var r = 0; r < n; r++)
        {
         
          // for space
          for (var i = r; i < n - 1; i++)
          {
            document.write("  ");
            document.write(" ");
          }
 
          // for $
          for (var i = 0; i < 2 * r + 1; i++) document.write("$ ");
 
          // new line
          document.write("<br>");
        }
 
        // for middle body
        // $           $
        // $ $       $ $
        // $ $ $   $ $ $
        // $ $ $ $ $ $ $
        // $ $ $   $ $ $
        // $ $       $ $
        // $           $
        for (var r = 0; r < 2 * n - 1; r++)
        {
          if (r < n - 1)
          {
           
            // for body
            // $           $
            // $ $       $ $
            // $ $ $   $ $ $
 
            // for $
            for (var i = 0; i <= r; i++) document.write("$ ");
 
            // for space
            for (var i = 0; i <= 2 * (n - r - 1) - 2; i++) {
              document.write("  ");
              document.write(" ");
            }
 
            // for $
            for (var i = 0; i <= r; i++) document.write("$ ");
          } else if (r == n - 1) {
            // for body
            // $ $ $ $ $ $ $
 
            // for $
            for (var i = 0; i < 2 * r + 1; i++) document.write("$ ");
          } else {
            // for body
            // $ $ $   $ $ $
            // $ $       $ $
            // $           $
 
            // for $
            for (var i = 2 * n - 1; i > r; i--) document.write("$ ");
 
            // for space
            for (var i = n; i <= r; i++) {
              document.write("  ");
              document.write(" ");
            }
 
            // for space
            for (var i = n; i < r; i++) {
              document.write("  ");
              document.write(" ");
            }
 
            // for $
            for (var i = 2 * n - 1; i > r; i--) document.write("$ ");
          }
 
          // new line
          document.write("<br>");
        }
 
        // for lower triangle
        // $ $ $ $ $ $ $
        //   $ $ $ $ $
        //     $ $ $
        //       $
 
        for (var r = 0; r < n; r++)
        {
         
          // for space
          for (var i = 0; i < r; i++) {
            document.write("  ");
            document.write(" ");
          }
 
          // for $
          for (var i = 0; i < 2 * (n - r) - 1; i++) document.write("$ ");
 
          // new line
          document.write("<br>");
        }
      }
 
      var n = 4;
      printPattern(n);
       
      // This code is contributed by rdtank.
    </script>
Output: 
      $ 
    $ $ $ 
  $ $ $ $ $ 
$ $ $ $ $ $ $ 
$           $ 
$ $       $ $ 
$ $ $   $ $ $ 
$ $ $ $ $ $ $ 
$ $ $   $ $ $ 
$ $       $ $ 
$           $ 
$ $ $ $ $ $ $ 
  $ $ $ $ $ 
    $ $ $ 
      $

 




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