users = []
users.append([username, password])

usersFile = open("users.txt","w+")
for users in users:
  usersFile.write("%s" % users)
usersFile.close()


def loginFunction():
    userEntry = ""

    foundName = 0

    while userEntry == "":
        userEntry = raw_input("Enter your username: ")
        usersFile = open("users.txt", "r")
        lines = usersFile.readlines()
        usersLen = len(users)
        for index in range (0, usersLen-1):
            if userEntry == users[index, 0]:
                foundName = 1
                passwordEntry = raw_input("Enter your password: ")
                if passwordEntry == users[index, 1]:
                    print "Username and passwords are correct"
                else:
                    print "incorrect"
                    userEntry = ""
        if foundName == 0:
            print "Username not recognised"
            userEntry = ""