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Program to print the pattern with two hollow Triangles

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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 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: 

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

 

Time Complexity : O(n2)
Auxiliary Space : O(1)



Last Updated : 13 Mar, 2023
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