要求：顾客可以根据商品编号购买工资允许内的商品，购买完成后，打印购买列表。

def main():
    salary = input("what is your salary ?")
    if salary.isdigit():
        salary = int(salary)
    else:
        print("请输入数字！")
    shopping_list = [("iphone",5000),
                     ("notebook",8000),
                     ("coffee",30),
                     ("book",50),
                     ("bike",500)
    ]
    print(shopping_list)
    shopping_cart = []
    for i in shopping_list:
        print("商品编号：",shopping_list.index(i),"价格为:",shopping_list[shopping_list.index(i)][1])
        question = input("do you want it ?(yes/no)")
        if question == "yes" :
            if shopping_list[shopping_list.index(i)][1] > salary:
                print("余额不足！")
            else:
                print("购买成功！")
                salary = salary - shopping_list[shopping_list.index(i)][1]
                shopping_cart.append(shopping_list[shopping_list.index(i)])
        elif question == "no":
            question2 = input("do you want to exit?(yes/no)")
            if question2 == "yes":
                break
            else:
                continue
        else:
            print("输入错误")
    print("you have bought:",shopping_cart)

if __name__ == "__main__":
    main()