C++ Program to Print Christmas Tree Using Pyramid

Christmas is a season of joy and festivities, and what better way to celebrate it as a programmer than by creating a Christmas tree pattern using C++? In this article, we will learn how to print a Christmas tree pattern of desired height using simple nested loops in C++.

Approach to Print Christmas Tree

The tree consists of a series of pyramid structures stacked together, with a trunk at the bottom to complete the festive look. This complex task can be simplified by breaking the tree into parts can make it a bit easy.

Printing Upper Part (Pyramids): printTop() Function

First, we take 4 variables to control the tree structure

• height: Specifies the number of pyramid levels in the tree. It is given by the user, but the default value is set to 5.
• width: Starting width for the topmost pyramid level is 5. This grows as we move down the tree.
• space: Controls the alignment of the tree. It starts as width * 5, ensuring the tree is centered.
• x: Controls the width of each row in the whole pyramid. It ensure the tree widens as it goes down.

The pyramid part is then printed by:

• Outermost loop prints the level/number of the pyramid
  • Inner loop iterates through each row of the pyramid.
    • Innermost loops are used to manage spaces and asterisks for each row.
    • The first innermost loop handles printing spaces before the asterisks to centre them.
    • The second innermost loop prints the asterisks in a pyramid pattern.

Printing Lower Part (Trunk): printTrunk() Function

• A loop is used to print the lower part of the tree, which represents the tree trunk. It prints 4 rows for the trunk.
  • First inner loop is used to align the trunk centrally below the tree by printing spaces.
  • Second inner loop prints a fixed number of stars (4) to form the rectangular trunk.

The whole program is enclosed inside a class ChristmasTree and printTrunk() and printTop() functions are called by the print() function.

Program to Print Christmas Tree Using Pyramids

#include <iostream>
using namespace std;

// Class to print chritmas tree
class ChristmasTree {
  public:
    ChristmasTree(int h = 5) {
        height = h;
    }

    void printTrunk(int width) {

        // Assign the space to be left at start
        int space = width * 5;

        // Printing the trunk of chritmas tree
        for (int i = 1; i <= 4; i++)
        {

            for (int j = space - 3; j >= 1; j--)
                cout << " ";

            for (int k = 1; k <= 4; k++)
                cout << "* ";

            cout << endl;
        }
    }

    void printTop(int width) {

        // Assign the space to be left at start
        int space = width * 5;

        // Number of cells in each row
        int x = 1;

        // Code to Print Upper Part of the Tree i.e.
        // Pyramids.
        for (int a = 1; a <= height; a++) {
            for (int i = x; i <= width; i++) {

                for (int j = space; j >= i; j--)
                    cout << " ";

                for (int k = 1; k <= i; k++)
                    cout << "* ";

                cout << endl;
            }
            x = x + 2;
            width = width + 2;
        }
    }

  	// Function to print the tree
    void print() {
        printTop(5);
      	printTrunk(5);
    }

  private:
    int height;
};

int main() {

    // Create a ChristmasTree object of desired height
    ChristmasTree c(4);

    // Print the tree
    c.print();
    return 0;
}

Output:

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