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

您需要包含圆括号才能调用 function：

else:
    wrong_sign()

Answer 2

您应该更改您的 elif 语句之一：

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

Answer 3

在最后一行，你必须调用wrong_sign() function：

else:
    wrong_sign()

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()

Output 为无效符号

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
​