Python 计算器除以零/对 Neg 求平方。诠释。程序崩溃

Question

好吧，我正在为一个项目做这个，每当我试图让它除以零或平方根一个负数时，程序就会关闭。我试图找到一些我可以插入到代码中的东西，让它显示一条消息，然后再次提示输入值，但是我尝试插入的所有内容都会导致程序在我启动时立即关闭。

这是没有插入任何东西来修复崩溃的计算器。

import math

def convertString(str):
    try:
        returnValue = int(str)
    except ValueError:
        returnValue = float(str)
    return returnValue

def addition(a, B):
    return convertString(a) + convertString(B)

def subtraction(a, B):
    return convertString(a) - convertString(B)

def multiplication(a, B):
    return convertString(a) * convertString(B)

def division(a, B):
    return convertString(a) / convertString(B)

def sqrt(a):
    return math.sqrt(convertString(a))

keepProgramRunning = True

print "Welcome to [Removed]'s 2011 4-H Project! This is a simple calculator coded in  Python, which is a high-level programming language. Java, C, C++, and Perl are  other high-level programming languages that you may have heard of."

while keepProgramRunning:
    print ""
    print "Please choose what you would like to do:"
    print ""
    print "1) Addition"
    print "2) Subtraction"
    print "3) Multiplication"
    print "4) Division"
    print "5) Square Root"
    print "6) Quit Program"

    choice = raw_input()    

    if choice == "1":
        numberA = raw_input("Enter your first addend: ")
        numberB = raw_input("Enter your second addend: ")
        print "The sum of those numbers is:"
        print addition(numberA, numberB)
    elif choice == "2":
        numberA = raw_input("Enter your first term: ")
        numberB = raw_input("Enter your second term: ")
        print "The difference of those numbers is:"
        print subtraction(numberA, numberB)
    elif choice == "3":
        numberA = raw_input("Enter your first factor: ")
        numberB = raw_input("Enter your second factor: ")
        print "The product of those numbers is:"
        print multiplication(numberA, numberB)
    elif choice == "4":
        numberA = raw_input("Enter your dividend: ")
        numberB = raw_input("Enter your divisor: ")
        print "The quotient of those numbers is:"
        print division(numberA, numberB)
    elif choice == "5":
        numberA = raw_input("Enter the number you wish to find the square root of: ")
        print "Your result is:"
        print sqrt(numberA)
    elif choice == "6":
        print "Goodbye! Thank you for your time spent both judging my project and those of everyone else! Have a nice day! (｡◕‿◕｡)"
        keepProgramRunning = False
    else:
        print "Please choose a valid option."
        print "\n"

我不确定要插入什么以及在哪里解决崩溃问题，但我认为问题在于我的位置。

我一直在尝试插入这样的内容:

except ValueError:
            print "You cannot divide by zero. Please choose another divisor."
            numberB = raw_input("Enter your divisor: ")

那行得通吗？我会在哪里插入它？如果它不起作用，它会怎样，会去哪里？

我一直想把它放在后面

numberB = raw_input("Enter your divisor: ")

所以该部分将阅读

elif choice == "4":
    numberA = raw_input("Enter your dividend: ")
    numberB = raw_input("Enter your divisor: ")
        except ValueError:
            print "You cannot divide by zero. Please choose another divisor."
            numberB = raw_input("Enter your divisor: ")
    print "The quotient of those numbers is:"
    print division(numberA, numberB)

但正如我所说，当我尝试这样做时，程序会在打开后立即关闭。另外，我知道如果他们再次输入 0，程序就会崩溃。有什么办法让它回到它所在的那一行吗？

此外，对于关闭程序，由于程序在显示后立即关闭，或者命令正在同时执行，因此无法读取应该显示的消息。无论哪种方式，都无法读取消息。有什么方法可以使消息出现在单独的对话框窗口中，从而导致程序在窗口关闭时关闭？或者至少是一种让它在关闭前延迟的方法？

如果我有任何术语错误，请纠正我。我对此还是有些陌生。

而且，一如既往，我们始终欢迎对计划任何部分的(建设性)反馈。

Answer 1

问题是您试图在抛出异常之前捕获它。相反，试试这个:

elif choice == "4":
    numberA = raw_input("Enter your dividend: ")
    numberB = raw_input("Enter your divisor: ")
    while float(numberB) == 0:
        print "You cannot divide by zero. Please choose another divisor."
        numberB = raw_input("Enter your divisor: ")
    print "The quotient of those numbers is:"
    print division(numberA, numberB)