Merry Christmas (Program for Christmas Tree in C)

Since Christmas is right at the door, its time to celebrate it in the programmer’s way. Lets build a decorative Christmas tree in C. To print a Christmas tree, we are printing pyramids of various sizes just one beneath the other. For the decoration, a random character is printed at each position. Height and randomness can be adjusted. This is been repeated frame after frame to give the illusion of a true event. Example: Lets see the code. 

C

// C program to print a Christmas tree
// It is recommended is try it with a desktop
// compiler like CodeBlocks.
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <unistd.h>

#define RefRate 40000
#define randomness 5 // high means less random

// Clear the shell
void clrscr()
{
    system("@cls||clear");
}

// Print a random character giving preference
// to *
void printRandLeaf()
{
    char leaftypes[5] = { '.', '*', '+', 'o', 'O' };
    int temp = rand() % randomness;

    // Giving preference to *
    if (temp == 1)
        printf("%c ", leaftypes[rand() % 5]);
    else
        printf("%c ", leaftypes[1]);
}

void triangle(int f, int n, int toth)
{
    int i, j, k = 2 * toth - 2;

    for (i = 0; i < f - 1; i++)
        k--;

    // number of rows
    for (i = f - 1; i < n; i++) {

        // space handler
        for (j = 0; j < k; j++)
            printf(" ");

        // decrementing k after each loop
        k = k - 1;

        // number of columns, printing stars
        for (j = 0; j <= i; j++)
            printRandLeaf();

        printf("\n");
    }
}

// Prints multiple triangles
void printTree(int h)
{
    int start = 1, stop = 0, diff = 3;
    while (stop < h + 1) {
        stop = start + diff;
        triangle(start, stop, h);
        diff++;
        start = stop - 2;
    }
}

// Prints bottom part.
void printLog(int n)
{
    int i, j, k = 2 * n - 4;

    for (i = 1; i <= 6; i++) {

        // space handler
        for (j = 0; j < k; j++)
            printf(" ");

        for (j = 1; j <= 6; j++)
            printf("#");

        printf("\n");
    }
}

// Driver code
int main()
{
    srand(time(NULL));
    int ht = 6;

    printf("\n*********MERRY CHRISTMAS*********\n\n");

    // refresh loop
    while (1) {
        clrscr();
        printTree(ht);

        printLog(ht);
        usleep(RefRate);
    }

    return 0;
}

Complexity analysis of the main code to print a tree of height h

Time Complexity: O(h³)
Auxiliary Space: O(1), As constant extra space is used.