我的 else 不工作，但没有显示任何错误标志。如果，elif 工作正常。python是我的代码

Question

print("Calculator for substraction, addition, multiplication and division")sign=input("Enter a sign:")num1=float(input("Enter a number:"))num2=float(input("Enter a second number:"))def wrong_sign():    print("Sign entered is invalid please use one of those 1. - for substraction \n 2. + for addition \n 3. x or * for multiplication \n 4. / for devision")if sign == "-":    print(num1-num2)elif sign == "+" :    print(num1+num2)elif sign == "/":    print(num1/num2)elif sign == "*" or "x":    print(num1 * num2)else:     wrong_sign 仅当我尝试输入无效符号时，没有代码错误，因为用户什么也没有出现，并且 wrong_sign 代码不显示。

Answer 1

您需要包含圆括号来调用函数：

else:
    wrong_sign()

Answer 2

在最后一行，你必须调用wrong_sign()函数：

else:
    wrong_sign()

Answer 3

您应该更改您的 elif 语句之一：

elif sign == "*" or sign == "x":

Answer 4

这是您的正确代码

print("Calculator for substraction, addition, multiplication and division")

sign=input("Enter a sign:")

num1=float(input("Enter a number:"))

num2=float(input("Enter a second number:"))

def wrong_sign():

    print("Sign entered is invalid please use one of those 1. - for substraction \n 2. + for addition \n 3. x or * for multiplication \n 4. / for devision")

if sign == "-":

    print(num1-num2)

elif sign == "+" :

    print(num1+num2)

elif sign == "/":

    print(num1/num2)

elif sign == "*" or sign == "x":

    print(num1 * num2)

else: 

    wrong_sign()

无效符号的输出

Calculator for substraction, addition, multiplication and division

Enter a sign:$

Enter a number:2

Enter a second number:3

Sign entered is invalid please use one of those 1. - for substraction 

 2. + for addition 

 3. x or * for multiplication 

 4. / for devision