import sys
import random

#
# Author:  James Tam
# Version: March 3, 2010
# A program that uses a 2x2 list to represent a randomly generated character-
# based world.

MAX_ROWS = 4
MAX_COLUMNS = 4
NO_COMBINATIONS = 10

# function generateElement
# Maps an integer value to a character value.
# Although the precondition for this function is that the number is within the
# range of 1 - 10, an error message is generated for values outside those
# bounds.
def generateElement (temp):
    anElement = '?'
    if (temp >= 1) and (temp <= 6):
        anElement = ' '
    elif (temp >= 7) and (temp <= 9):
        anElement = '*'
    elif (temp == 10):
        anElement = '.'
    else:
        print "<< Error with the random no. generator.>>"
        print "<< Value should be 1-10 but random value is ", temp
        anElement = '!'
    return anElement

# Traverses the grid and randomly sets each element to one of the following
# values:
# 60% chance the element will contain a space.
# 30% chance the element will contain a star.
# 10% chance the element will contain a dot.
# If the element contains an exclaimation mark then there was an error
# with the random number generator.
def initialize (aGrid):
    for r in range (0, MAX_ROWS, 1):
        for c in range (0, MAX_COLUMNS, 1):
            temp = random.randint(1, NO_COMBINATIONS)
            aGrid[r][c] = generateElement(temp)


def display (aGrid):
    for r in range (0, MAX_ROWS, 1):
        for c in range (0, MAX_COLUMNS, 1):
            sys.stdout.write(aGrid[r][c])
        print

def displayLines (aGrid):
    for r in range (0, MAX_ROWS, 1):
        print " - - - -"
        for c in range (0, MAX_COLUMNS, 1):
            sys.stdout.write ('|')
            sys.stdout.write (aGrid[r][c])
        print '|'
    print " - - - -"

# MAIN FUNCTION

# Create a reference to a 1D array
aGrid = []

# Loop:
# Each iteration of the outer loop creates one row and adds it
# to the array.
# Each iteration of the inner loop then steps through each element.
# of the the row and creates and intializes the elements for the
# row.
for r in range (0, MAX_ROWS, 1):
    aGrid.append ([])
    for c in range (0, MAX_COLUMNS, 1):
        aGrid[r].append (" ")

initialize(aGrid)
print "Displaying grid"
print "==============="   

display (aGrid)
print 
print "Displaying grid with bounding lines"
print "==================================="   
displayLines (aGrid)