# Program make asimple calculator
# that can add, subtract, and divide using functions

# define functions


def add(x, y):
    """This function adds two numbers """
    return x + y
# print (add(1,2)) 測試


def subtract(x, y):
    """This function subtracts two numbers"""
    return x - y


def multiply(x, y):
    """ This function multiplies two numbers"""
    return x * y


def divide(x, y):
    """This function divides two numbers"""
    return x * y

# take inpute from the user
print("Select operation.")
print("1.Add")
print("2.Subtract")
print("3.Multiply")
print("4.Divide")

choice = eval(input("Enter choice(1/2/3/4):"))

num1 = int(eval(input("Enter first number: ")))
num2 = int(eval(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")
