/**
 * A class that performs repeated random alley walk simulations (using an
 * AlleyWalker object) and calculates the average number of steps required
 * for each walk.
 *   @author Dave Reed
 *   @version 11/7/06
 */
public class WalkStats
{
	private int alleyLength;
	private AlleyWalker walker;

	/**
	 * Constructs a WalkStats object.
	 *   @param distance the goal distance for the RandomWalker
	 */
	public WalkStats(int distance) {
		this.alleyLength = distance;
		this.walker = new AlleyWalker();
	}

	/**
	 * Gets the length of the alley the walker is in.
	 *   @return the alley length (from the middle to either end)
	 */
	public int length() {
	    return this.alleyLength;
	}
	   
	/**
	 * Simulates a number of random walks and maintains statistics.
	 *   @param numWalks the number of walks to be simulated
	 *   @return the average number of steps required for the walks
	 */
	public double averageSteps(int numWalks) {
	    if (numWalks <= 0) {
	        return 0.0;
	    }
	    else {
		    int totalSteps = 0;
		    for (int walk = 1; walk <= numWalks; walk++) {
		        walker.reset();
		        walker.stepToDistance(this.length());
		        totalSteps += walker.getNumSteps();
		    }
		
		    return (double)totalSteps/numWalks;
		}
	}
}