坚持使用简单的 Python 程序"elif"

Question

您好，我在做简单的计算器代码时遇到了问题:D

def cal():
while True:
print ("welcome to my calculator!")
print("choose an operation")
op = input(" +, - ,/ ,*")

if op == "+":
num1 = float(input("enter your first number:"))
num2 = float(input("enter your second number:"))
print(str(num1 + num2)

elif op == "/":
num1 = float(input("enter your first number:"))
num2 = float(input("enter your second number:"))
print(str(num1 / num2)

else:
break 

cal()

当我运行代码时，它在elif处显示无效语法

这里出了什么问题？

Answer 1

您从未关闭打印功能的括号。另一个if声明也是如此。将来也应该使用 4 个空格的缩进。

if op == "+":
num1 = float(input("enter your first number:"))
num2 = float(input("enter your second number:"))
print(str(num1 + num2))

Answer 2

你错过了一堆括号。如果你想进一步提高你的程序，请使用它作为模型：

# This function adds two numbers 
def add(x, y):
return x + y
# This function subtracts two numbers 
def subtract(x, y):
return x - y
# This function multiplies two numbers
def multiply(x, y):
return x * y
# This function divides two numbers
def divide(x, y):
return x / y
print("Select operation.")
print("1.Add")
print("2.Subtract")
print("3.Multiply")
print("4.Divide")
# Take input from the user 
choice = input("Enter choice(1/2/3/4):")
num1 = int(input("Enter first number: "))
num2 = int(input("Enter second number: "))
if choice == '1':
print(num1,"+",num2,"=", add(num1,num2))
elif choice == '2':
print(num1,"-",num2,"=", subtract(num1,num2))
elif choice == '3':
print(num1,"*",num2,"=", multiply(num1,num2))
elif choice == '4':
print(num1,"/",num2,"=", divide(num1,num2))
else:
print("Invalid input")