Thread: Christmas tree with lights and balls

Hi everyone,

In Programming practicum we were given an assignment to make a program which displays a christmas tree with randomly drawn "+" and "o" which represent lights and balls. The result should look like this:



This is my code for the christmas tree itself, but I am struggling with the lights and balls. Maybe someone can help me out?

Code:

#include <stdio.h>
#include <stdlib.h>

int main()
{

    int ROWS, starNumber, spaceNumber;
    int rowCount, spaceCount, starCount, treeTrunkRows, treeTrunkSpaceCount;

    printf ("Enter number of rows: ");
    scanf ("%d", &ROWS );
    printf("\n");

    for(rowCount = 1; rowCount <= ROWS; rowCount++) {
        starNumber = rowCount * 2 - 1;
        spaceNumber = rowCount + ROWS - starNumber;

        for(spaceCount = 0; spaceCount < spaceNumber; spaceCount++)
            printf(" ");

        for(starCount = 0; starCount < starNumber; starCount++)
            printf("*");

        printf("\n");
    }

    for(treeTrunkRows = 0; treeTrunkRows < 2; treeTrunkRows++) {
        for(treeTrunkSpaceCount = 0; treeTrunkSpaceCount < (ROWS * 2 + 1)/2; treeTrunkSpaceCount++)
            printf(" ");
            printf("*\n");
    }
}

Suppose you want to generate 'light' with probability p, 'bulb' with probability q, and 'star' with probability 1-p-q.
At line 22 in your code, instead of printing '*', you could use rand() (or other auxiliary function) to generate number x in the range [0,M], now if 0 <= x < p*M then print 'light', else if p*M <= x < (p+q)*M then print 'bulb', else print 'star'.
Notice that this assumes you are uniformly sampling from [0,M], which is not always true for rand(), if I am not mistaken.