# Programmer: Sriram Pemmaraju
# Date: 3/5/2015

import random

# This function returns the length of a simulated 2-dimensional
# random walk with barriers at x = n, x = -n, y = n, and y = -n.
# The walker starts at location (0, 0) and the walk ends on hitting the
# barrier.
def twoDRandomWalk(n = 100, printOn = False):
    # Initial location of random walker
    locX = 0
    locY = 0
    
    length = 0 # length of random walk
    while abs(locX) < n and abs(locY) < n:
        # Pick one of the four directions at random and
        # walk one step in that direction
        direction = random.randint(1, 4)
        if direction == 1: # north
            locY = locY + 1
        elif direction == 2: # east
            locX = locX + 1
        elif direction == 3: # south
            locY = locY - 1
        elif direction == 4: # west
            locX = locX - 1
        if printOn:
            print(locX, locY)            
        length = length + 1
    
    return length