flipfunc.c

// flipfunc.c : Flips a coin

#include "time.h"
#include "stdio.h"
#include "stdlib.h"

double f(int, int *i, int *hist);

// Input: flips - how many times to flip the coin.
// Output:
//        *headsInARow - updates with a count of the longest run of heads in a row.
//        hist[] - updates a list of counts in a row history.
// Returns: odds of heads (should be near 50%)
double f(int flips, int *headsInARow, int hist[])
{
	int heads = 0;
	int currentRun = 0;
	for (int i = 0; i < flips; i++)
	{
		int flip = rand() % 2;
		if (flip == 1)
		{
			heads++;
			currentRun += 1;
		}
		else
		{
			if (currentRun > 2)
			{
			    hist[currentRun]++;
			    *headsInARow = (*headsInARow < currentRun) ? currentRun : *headsInARow;
			}
			currentRun = 0;
		}
	}	
	if (currentRun)
	{
		*headsInARow = (*headsInARow < currentRun) ? currentRun : *headsInARow;
		hist[currentRun]++;
	}

	return heads / (double) flips;
}