Python Sentinel值

Question

我是一名乞求Python学生创建一个程序来进行数学测验。测验本身有效，但我遇到的问题是继续测验，直到用户希望通过输入标记值退出。我已尝试在几个地方使用sentinel值，但程序完全停止或程序螺旋形成无限循环。只需要在哪里正确放置哨兵值的建议。

 import random 

 a = random.randint(1,15)
 b = random.rantint(1,15)

 c = a + b

  while flag != -1
     print("Enter the sum of", a, "+",b)

      d=int(input())
      if (c==d):
         print("Correct")
      else:
         print("Incorrect, the correct answer is", c)

      flag = int(input("If you would like to continue enter 1 or -1 to quit))

      if (flag < 0) :
         print ("Quiz complete")

Answer 1

查看以下内容是否有效

import random 

flag = 0
while flag != -1:
    a = random.randint(1,15)
    b = random.randint(1,15)
    c = a + b
    print("Enter the sum of", a, "+",b)
    d=int(input())
    if (c==d):
        print("Correct")
    else:
        print("Incorrect, the correct answer is", c)

    flag = int(input("If you would like to continue enter 1 or -1 to quit: "))

    if (flag < 0) :
        print ("Quiz complete")

Answer 2

如上所述，休息在这里很有帮助，

While True:
    flag = int(input())
    if(flag < 1):
       # This will break the While Loop, thus exiting the program
       break