#Python exercise 18 - Cow and Bull
import random

def score(num,rnd):
    cowsbull = [0,0]
    for i in range(len(rnd)):
        if num[i] == rnd[i]:
            cowsbull[0]+=1
        elif num[i] in rnd:
            cowsbull[1]+=1
    return print("Cows",cowsbull[0],"Bulls",cowsbull[1])


if __name__=="__main__":

    tryagain = 'Y'
    cnt = 0
    rd = str("%0.4d" % random.randint(0,9999))

    print("=================================")
    print("Welcome to the Cow and Bull game!")
    print("=================================""\n")
    print("To win, guess the four digit number""\n")
    print("Cows mean you have a correct digit in the right place""\n")
    print("Bulls mean the digit is right, but the wrong place""\n")

    while tryagain in ['Y','y']:
        gs = input("Please enter your guess or 'Q' to quit:  ")
        cnt += 1
        while len(gs) == 4 or gs not in ['Q','q']:
            if gs == rd:
                print("Congratulations, you've guessed the number in",cnt,"tries!")
                choice = input("Try again? Y/Any other key to quit: ")
                if choice in ['Y','y']:
                    tryagain = 'y'
                else:
                    break
            elif gs in ['Q','q']:
                break
            else:
                score(gs,rd)
                break
        else:
            if gs in ['Q','q']:
                break
            else:
                print("Invalid input - try again")
    print("Thanks for playing, come back soon")