简单的购物车程序

需求：

　　1. 启动程序后，让用户输入工资，然后打印商品列表

　　2. 允许用户根据商品编号购买商品

　　3. 用户选择商品后，检测余额是否足够，够就直接扣款，不够就提醒

　　4. 可随时退出，退出时，打印已购买的商品和余额

 

第一版：

__author__ = 'long.xie'
# -*- coding:utf-8 -*-

product_list=[
    ("Iphone",5888),
    ("Macbook",12000),
    ("Applewatch",3899),
    ("IPad",3999),
    ("Book",120)
]
shopping_list=[]
money=input("Input your money:")
if money.isdigit():
    money=int(money)
    while True:
        for id,item in enumerate(product_list):
            # print(product_list.index(item),item)
            print(id,item)
        user_choice=input("choose product id:")
        if user_choice.isdigit():
            user_choice=int(user_choice)
            # if user_choice>=0 and user_choice<=len(product_list):
            if 0<=user_choice<=len(product_list):
                price=product_list[user_choice][1]
                if money>=price:
                    shopping_list.append(product_list[user_choice])
                    money-=price
                    print("Added {_item} in cart, your balance is {_money}".format(_item=product_list[user_choice][0],_money=money))
                else:
                    print("your balance is not enough!")
            else:
                print("product code %s not exists!" % user_choice)
        elif user_choice=="q":
            print("---------shopping list----------")
            for item_bought in shopping_list:
                print(item_bought)
            exit("Your current balance: %s, See you!" %money)
        else:
            print("invalid option...")
else:
    print("invalid input...")