python之在我的 Python 应用程序中找不到名称

keepProgramRunning = True 
 
while keepProgramRunning: 
    print "Welcome to the Calculator!" 
    print "Please choose what you'd like to do:" 
 
    print "0: Addition" 
    print "1: Subtraction" 
    print "2: Multiplication" 
    print "3: Division"     
 
 
    #Capture the menu choice. 
    choice = raw_input() 
 
    #Capture the numbers you want to work with. 
    numberA = raw_input("Enter your first number: ") 
    numberB = raw_input("Enter your second number: ") 
 
    if choice == "0": 
        print "Your result is:" 
        print Addition(numberA, numberB) 
    elif choice == "1": 
        print "Your result is:" 
        print Subtraction(numberA, numberB) 
    elif choice == "2": 
        print "Your result is:" 
        print Multiplication(numberA, numberB) 
    elif choice == "3": 
        print "Your result is:" 
        print Division(numberA, numberB) 
    else: 
        print "Please choose a valid option." 
 
 
 
def Addition(a, b): 
    return a + b 
 
def Subtraction(a, b): 
    return a - b 
 
def Multiplication(a, b): 
    return a * b 
 
def Division(a, b): 
    return a / b 

这是错误:

Traceback (most recent call last): 
  File "C:\Users\Sergio.Tapia\Documents\NetBeansProjects\Tutorials\src\tutorials.py", line 23, in <module> 
    print Addition(numberA, numberB) 
NameError: name 'Addition' is not defined 

感谢您的帮助!

附言。我意识到循环永远不会结束，我还没有添加菜单选项。 :P

请您参考如下方法:

您需要在调用函数之前定义它们。

当解释器读取调用 Addition() 的行时，它还没有到达定义 Addition() 的行。因此它会抛出异常。