cows and bulls

gistfile1.txt

import random

def cab():
    a = int(random.randint(1000, 9999))
    print a
    
    status = False

    while status is False:
        i = input('Choose a 4 digit number: ')

        if i not in range(1000, 9999):
            print 'Incorrect number; choose again!'
            cab()
            
        cows = 0
        bulls = 0

        for j in range(4):
            if str(i)[j] == str(a)[j]:
                cows += 1
            elif str(i)[j] in str(a):
                bulls += 1

        if a == i:
            print 'You guessed the number'
            status = True
        else:
            print '%d cows; %d bulls' %(cows, bulls)
        
cab()