Question

C++

recursive function that draws the following shape.

X

XXX

XXXXX

XXXXXXX

XXXXXXXXX

XXXXXXXXX

XXXXXXX

XXXXX

XXX

X

The length of the longest row in the shape and the shape's character are function parameters.

In above shape the longest row is 9 and the pattern's character is "X".

Answer 1

Recurisive Function : This is a function that gets called during the execution. The process of this repeation takes several times during the execution. Once all the process is finished then only we will be getting the output.

PROGRAM SPECIFICATIONS:

In the implemention of the code I have provided some space after X its because for easy counting of the letter as it is mentioned the longest row is "9".It will become the output look more good enough also. Since I the question it is mentioned the code should be in C++. I have meet that criteria also.

PROGRAM CODE ;

#include <iostream> 
using namespace std; 

//Half pyramid recusion

//This function is for printing the half pyramid of X
void printn(int num) 
{ 
    //inital condition
    if (num == 0) 
        return; 
    cout << "X "; 
    printn(num - 1 ); 
} 
  
void pattern(int n, int i) 
{ 
    if (n == 0) 
        return; 
    //checking the condition using if loop    
    if(i%2!=0)
    {
        printn(i);
    }
    cout<<endl;
     pattern(n - 1 , i+1); 
} 
  
/* Here we are doing the inversion of the pyramid */
void printPatternInverted(int n, int i) 
{ 
    // intial  condition 
    if (n < 1) 
        return; 
      
    // to print the pattern of a particular row 
    if (i <= n && n%2!=0) 
    { 
        cout << "X "; 
        // recursively print rest of the stars  
        // of the row 
        printPatternInverted(n, i + 1); 
        
    }     
      
    else
    {   
        cout<<endl;
        // print the pattern of the remaining rows recursively 
        printPatternInverted(n-1, 1); 
    } 
} 

//main function begins here....
int main() 
{ 
    //declaration of variables
    int n = 9; 
    //calling the recurison function
    pattern(n , 1); 
    printPatternInverted(n, 1); 
    return 0; 
} 

PROGRAM SCREENSHOT :

I have done this program using online GDB complier and attaching the screenshot of input and output.

INPUT SCREENSHOT

OUTPUT SCREENSHOT