简单的购物车软件

salary=input("salary:")
if salary.isdigit():
    salary=int(salary)
else:
    exit("invaild")

welcome_msg="welcome".center(50,"-")
print(welcome_msg)

exit_flag= False
product_list=[
    ("mate10",4000),
    ("P20",4500),
    ("X",8000),
    ("MI",3000),
    ("+6",2888),
    ("mac pro",10000)]
while not exit_flag:
    print("product list".center(30,"-"))
    for item in enumerate(product_list):
        index=item[0]
        product_name=item[1][0]
        product_price=item[1][1]
        print(index,product_name,product_price)

    user_choose=input("what do you want:")
    if user_choose.isdigit():
        user_choose=int(user_choose)
        if user_choose< len(product_list):
            product_item=product_list[user_choose]
            if product_item[1]<salary:
                shop_cart.append(product_item)
                salary-=product_item
                print("add", product_item, "into the shop cart and your rest money is:",salary)
            else: print("your money is not enough")
    if user_choose=="Q" or "Quit":
        print("You have already purchased below items:".center(30,"~"))
        for item in shop_cart:
            print(item)
        print("end".center(30,"-"))
        print("see you again")
        exit_flag= True
    elif user_choose=="C" or "Check":
        print("You have already purchased below items:".center(30,"~"))
        for item in shop_cart:
            print(item)
        print("end".center(30, "-"))
        print("see you again")