Program to print the pattern with two hollow Triangles

Last Updated : 13 Mar, 2023

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:

The above triangle

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

This is done with the help of for loop for rows 0 to n-1. Firstly the space is printed, then the ‘$’ is printed.
The middle body

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

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.

The lower triangle

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

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)

Program to print hollow rectangle or square star patterns

VipinKashyap

Improve

Article Tags :

Practice Tags :

pattern-printing

Program to print the pattern with two hollow Triangles

C++

Java

Python3

C#

PHP

Javascript

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