# randomize the lines in a file
# input file is list.txt, output file is listu.txt
# Matt Bishop, ECS 10, Fall 2012
import random

def main():
    #
    # open the file and read in the lines
    #
    try:
        # file to read
        f = open("list.txt", "r")
        flines = f.readlines()
        num = len(flines)
        # file to write
        g = open("listu.txt", "w")
    except Exception as errmsg:
        print(errmsg)
        return
    #
    # randomize the order of the lines
    # doing it num times is probably overkill!
    #
    for i in range(num):
        line1 = random.randrange(num)
        line2 = random.randrange(num)
        flines[line1], flines[line2] = flines[line2], flines[line1]

    #
    # now write out the lines
    #
    try:
        g.writelines(flines)
    except Exception as errmsg:
        print(errmsg)
        return
    #
    # clean up and quit
    #
    f.close()
    g.close()

main()