购物车程序(我都觉得丑的代码)：包含商家接口和买家接口

购物车要求：
 顾客接口：    
　1、读取商品列表(从文件中读取);
　2、新用户输入工资，如果老用户，记录上次余额；
商家接口：    
　1、增加商品；
　2、修改商品价格。

#商品文件内容
iphone 5800
coffee 50
watch 3000
car 300000
duck 45
fish 6
women 7000

#用户名、密码、余额文件
yb 1234 5000
bigd 1234 12000
jack 123456 8000

#Author BigD
# -*- coding:utf-8 -*-

# 购物车要求：
#     顾客接口：
#         1、读取商品列表(从文件中读取);
#         2、新用户输入工资，如何不是，记录上次余额
#     商家接口：
#         1、增加商品；
#         2、修改商品价格

def show_menu():
    shop_list = []
    shop_menu_file = open("shop_menu", "r")
    for shop_line in shop_menu_file:  # 遍历将内容写入列表
        shop_list.append(shop_line.strip().split(' '))
    # print(shop_list)
    print("shopping list".center(40, "="))
    for i in shop_list:  # 展示商品信息
        print(i[0], i[1])
    # print(shop_list)
    return shop_list

def write_shop_menu():
    shop_menu_ok = ""
    for shop_list_line in shop_list:
        line = str(shop_list_line[0]) + " " + str(shop_list_line[1]) + "
"
        shop_menu_ok += line
    open("shop_menu", "w").write(shop_menu_ok)

while True:
    use_type = input("who are you ?boss(b) or customer(c)?")
    if use_type == "b":
        print("welcome BOSS!")
        while True:
            shop_list = show_menu()
            # print(shop_list)
            boss_choice = input("Do you want add(a) product or modify(m) price?")
            if boss_choice == "a":
                product_name = input("enter the product name?")
                product_price = input("enter the price?")
                shop_list.append([product_name,product_price])
                write_shop_menu()
            elif boss_choice == "m":
                change_product = input("which product do you want to modify?")
                change_price = input("what price do you want to change?")
                for i in shop_list:
                    if i[0] == change_product:
                        i[1] = change_price
                # show_menu = show_menu()
                write_shop_menu()
            else:
                print("wrong!")

    elif use_type == "c":
        print("wecome CUSTOMER
")
        while True:
            user_list = []
            for user in open("user_menu","r"):
                user_list.append(user.strip().split(" "))
            print(user_list)

            g_name = input("what is your name ?")
            salary = ""

            for p in user_list:
                if p[0] == g_name:
                    name = g_name
                    passwd_count = 3
                    while True:

                        if passwd_count > 0:

                            passwd = input("what is your password?")
                            if passwd == p[1]:
                                salary = int(p[2])
                                print("your salary is %d" %salary)
                                break
                            else:
                                passwd_count -= 1
                                print("your password is wrong,you have %d times to try." % passwd_count)

                        else:
                            exit()
                else:
                    pass

            if salary == "":
                name = g_name
                salary = int(input("you are first come ,enter your salary."))


            # print(name)
            # print(salary)

            ok_menu = []
            while True:
                shop_list = show_menu()
                choose_product = input("you have $%s,what do you want to buy?" % salary)

                for i in shop_list:
                    if i[0] == choose_product:
                        if int(i[1]) < salary:
                            salary -= int(i[1])
                            ok_menu.append(i[0])
                            print(ok_menu)
                        else:
                            print("余额不足，请重新选择")
                if choose_product == "q":
                    print(ok_menu)
                    exit("bye")


    else:
        print("wrong choice.")

技术还是欠缺，写写停停，耽误了挺久，写的不好，看客莫介意，功能肯定还是欠缺的，看了一点函数，优化了一点，就到这儿吧，后面再完善补全。