如何修復Python中的無限循環？

Question

我正在用Python開發一個登錄安全程序，而這部分總是陷入無限循環中。 如果您被鎖定，它會一直說“您已被鎖定10秒鍾”，並且無限循環。 我該如何解決？

tries=0
while finalusername!=username or  finalpassword!=password:
tries=tries+1
print "That incorrect. Try again."
print "You have", 5-tries, "tries left."
finalusername= raw_input ("Username:")
finalpassword= raw_input ("Password:") 
while tries>=4:
    print "You have been locked out for 10 seconds. Please call the administrator if this keeps happening."
    sleep (10.0)
    system ('CLS')
    finalusername!=username
    finalpassword!=password

Answer 1

容易，改變

  while tries>=4:

至

  if tries >= 4:

如果你按照你的代碼，當你進入你的第二個while循環，變量的嘗試值不會改變，所以你會留在了那里所有的永恆。 如果將while更改為if，則將執行if語句的主體，然后繼續循環。

Answer 2

當tries大於4時，您的第二個while循環會激活，但是循環本身永遠不會對tries或包含任何其他退出條件。 這就是為什么它變得無限大的原因。 因此tries保持在4以上，循環永遠不會停止。

從您的代碼看來，在他們用盡嘗試之后，他們被鎖定了10秒鍾，然后又可以重新開始了？ 如果是這樣，您希望像這樣調整代碼：

tries=0
while finalusername!=username or  finalpassword!=password:
    tries=tries+1
    print "That incorrect. Try again."
    print "You have", 5-tries, "tries left."
    finalusername= raw_input ("Username:")
    finalpassword= raw_input ("Password:") 
    if tries>=4:
        print "You have been locked out for 10 seconds. Please call the administrator if this keeps happening."
        sleep (10.0)
        system ('CLS')
        tries = 0 #Reset tries counter
        finalusername!=username #I don't think this part is required
        finalpassword!=password #I don't think this part is required

Answer 3

我認為您應該在睡眠后將try設置為0，並在不需要時進行循環。 睡眠后，用戶應再次嘗試5次。

import os
import time

tries=0
finalusername, finalpassword= 'a', 'a'
username, password = None, None


while True:
    finalusername= raw_input ("Username:")
    finalpassword= raw_input ("Password:") 
    if finalpassword == username and finalpassword == password:
        break
    tries=tries+1
    print "That incorrect. Try again."
    print "You have", 5-tries, "tries left."
    if tries>=5:
        print "You have been locked out for 10 seconds. Please call the administrator if this keeps happening."
        time.sleep (10.0)
        os.system('cls')
        tries = 0