⬅️ 上一课下一课 ➡️
第30课：阶段项目——智能收银系统
🎯 本课目标
- 综合运用第三阶段所有条件判断知识
- 制作完整的智能收银系统
- 实现商品管理和选购功能
- 添加折扣和优惠计算逻辑
- 制作找零和小票打印功能
🤔 趣味引入：超市里的"智慧"
想象一下：你去超市购物时，收银员是怎么工作的？
- 🛒 扫描商品 → 识别每件商品的价格
- 💰 计算总额 → 把所有商品价格加起来
- 🏷️ 打折优惠 → 根据促销活动减价
- 💵 收取付款 → 收钱并计算找零
- 🧾 打印小票 → 列出所有购物明细
今天，让我们一起用Python制作智能收银系统，成为超市的"金牌收银员"！
🔧 第一部分：商品管理系统
1.1 商品数据库
# 商品数据库
print("🏪 商品管理系统")
print("=" * 50)
# 商品数据：编号、名称、单价、单位
products = {
"001": {"name": "苹果", "price": 5.00, "unit": "斤", "category": "水果"},
"002": {"name": "香蕉", "price": 3.50, "unit": "斤", "category": "水果"},
"003": {"name": "牛奶", "price": 12.00, "unit": "盒", "category": "饮品"},
"004": {"name": "面包", "price": 8.00, "unit": "个", "category": "食品"},
"005": {"name": "鸡蛋", "price": 1.50, "unit": "个", "category": "食品"},
"006": {"name": "可乐", "price": 3.00, "unit": "瓶", "category": "饮品"},
"007": {"name": "薯片", "price": 6.00, "unit": "袋", "category": "零食"},
"008": {"name": "巧克力", "price": 15.00, "unit": "块", "category": "零食"},
"009": {"name": "大米", "price": 3.00, "unit": "斤", "category": "粮油"},
"010": {"name": "食用油", "price": 45.00, "unit": "桶", "category": "粮油"}
}
def display_products():
"""显示所有商品"""
print(f"\n{'='*60}")
print(f"{'📋 商品列表':^60}")
print(f"{'='*60}")
print(f"{'编号':<6} {'名称':<10} {'单价':>8} {'单位':<6} {'类别':<10}")
print(f"{'-'*60}")
for code, info in products.items():
print(f"{code:<6} {info['name']:<10} ¥{info['price']:>6.2f} /{info['unit']:<4} {info['category']:<10}")
def search_product(keyword):
"""搜索商品"""
results = []
for code, info in products.items():
if keyword in info['name'] or keyword in info['category']:
results.append((code, info))
return results
def get_product_by_code(code):
"""根据编号获取商品"""
return products.get(code)
# 显示商品
display_products()
# 搜索功能演示
print("\n🔍 搜索示例：")
keyword = input("输入关键词搜索商品：")
results = search_product(keyword)
if results:
print(f"\n找到{len(results)}个商品：")
for code, info in results:
print(f" {code} {info['name']} ¥{info['price']}/ {info['unit']}")
else:
print("❌ 未找到相关商品")1.2 购物车管理
# 购物车管理
print("\n🛒 购物车管理系统")
print("=" * 50)
class ShoppingCart:
"""购物车类"""
def __init__(self):
self.items = {} # {code: {"product": info, "quantity": 数量}}
self.member_discount = 0 # 会员折扣（百分比）
self.coupon_discount = 0 # 优惠券折扣（金额）
def add_item(self, product_code, quantity=1):
"""添加商品到购物车"""
product = get_product_by_code(product_code)
if not product:
return False, "❌ 商品编号不存在！"
if quantity <= 0:
return False, "❌ 数量必须大于0！"
if product_code in self.items:
self.items[product_code]["quantity"] += quantity
else:
self.items[product_code] = {
"product": product,
"quantity": quantity
}
return True, f"✅ 已添加 {product['name']} × {quantity}{product['unit']}"
def remove_item(self, product_code, quantity=1):
"""移除商品"""
if product_code not in self.items:
return False, "❌ 购物车中没有该商品！"
current_qty = self.items[product_code]["quantity"]
if quantity >= current_qty:
del self.items[product_code]
return True, "✅ 已从购物车移除该商品"
else:
self.items[product_code]["quantity"] -= quantity
product = self.items[product_code]["product"]
return True, f"✅ 已移除 {product['name']} × {quantity}"
def update_quantity(self, product_code, new_quantity):
"""更新商品数量"""
if product_code not in self.items:
return False, "❌ 购物车中没有该商品！"
if new_quantity <= 0:
return self.remove_item(product_code, self.items[product_code]["quantity"])
self.items[product_code]["quantity"] = new_quantity
product = self.items[product_code]["product"]
return True, f"✅ 已更新 {product['name']} 数量为 {new_quantity}"
def get_subtotal(self):
"""计算小计（折扣前）"""
subtotal = 0
for code, item in self.items.items():
subtotal += item["product"]["price"] * item["quantity"]
return subtotal
def get_discount_amount(self):
"""计算折扣金额"""
subtotal = self.get_subtotal()
# 会员折扣
member_saving = subtotal * (self.member_discount / 100)
# 优惠券折扣
coupon_saving = min(self.coupon_discount, subtotal - member_saving)
return member_saving + coupon_saving
def get_total(self):
"""计算应付总额"""
subtotal = self.get_subtotal()
discount = self.get_discount_amount()
return subtotal - discount
def set_member_discount(self, discount_percent):
"""设置会员折扣"""
if 0 <= discount_percent <= 100:
self.member_discount = discount_percent
return True
return False
def set_coupon_discount(self, discount_amount):
"""设置优惠券"""
if discount_amount >= 0:
self.coupon_discount = discount_amount
return True
return False
def clear_cart(self):
"""清空购物车"""
self.items.clear()
self.member_discount = 0
self.coupon_discount = 0
def get_items_count(self):
"""获取商品种类数"""
return len(self.items)
def get_total_quantity(self):
"""获取商品总数量"""
return sum(item["quantity"] for item in self.items.values())
def display_cart(self):
"""显示购物车内容"""
if not self.items:
print("🛒 购物车是空的")
return
print(f"\n{'='*60}")
print(f"{'🛒 购物车内容':^60}")
print(f"{'='*60}")
print(f"{'编号':<6} {'商品':<10} {'单价':>8} {'数量':>6} {'小计':>10}")
print(f"{'-'*60}")
for code, item in self.items.items():
product = item["product"]
quantity = item["quantity"]
line_total = product["price"] * quantity
print(f"{code:<6} {product['name']:<10} ¥{product['price']:>6.2f} ×{quantity:>4} ¥{line_total:>8.2f}")
print(f"{'-'*60}")
print(f"{'小计':>38} ¥{self.get_subtotal():>8.2f}")
if self.member_discount > 0:
member_saving = self.get_subtotal() * (self.member_discount / 100)
print(f"{'会员折扣':>38} -¥{member_saving:>8.2f}")
if self.coupon_discount > 0:
print(f"{'优惠券':>38} -¥{self.coupon_discount:>8.2f}")
print(f"{'='*60}")
print(f"{'应付总额':>38} ¥{self.get_total():>8.2f}")
print(f"{'='*60}")
# 测试购物车
cart = ShoppingCart()
print("🛒 购物车操作演示：")
print("-" * 40)
# 添加商品
cart.add_item("001", 3) # 3斤苹果
cart.add_item("003", 2) # 2盒牛奶
cart.add_item("007", 1) # 1袋薯片
# 显示购物车
cart.display_cart()
# 设置折扣
print("\n💡 设置会员折扣（9折）：")
cart.set_member_discount(10)
cart.display_cart()
# 设置优惠券
print("\n💡 设置优惠券（减5元）：")
cart.set_coupon_discount(5)
cart.display_cart()📊 第二部分：收银结算系统
2.1 完整的收银流程
# 收银结算系统
print("\n💳 收银结算系统")
print("=" * 50)
class CashRegister:
"""收银机类"""
def __init__(self):
self.cart = ShoppingCart()
self.receipt_number = 0
self.daily_sales = 0
self.transaction_history = []
def scan_item(self):
"""扫描商品"""
print("\n📦 扫描商品")
print("输入商品编号添加，输入'done'完成扫描")
while True:
code = input("\n请输入商品编号（或'done'）：")
if code.lower() == "done":
break
product = get_product_by_code(code)
if not product:
print("❌ 商品编号不存在！")
continue
print(f"📋 {product['name']} ¥{product['price']}/{product['unit']}")
try:
quantity = float(input(f"数量（{product['unit']}）："))
success, message = self.cart.add_item(code, quantity)
print(message)
except ValueError:
print("❌ 请输入有效的数量！")
def apply_discounts(self):
"""应用折扣"""
print("\n🏷️ 折扣优惠")
print("1. 会员折扣")
print("2. 优惠券")
print("3. 跳过")
choice = input("请选择（1-3）：")
if choice == "1":
try:
discount = float(input("会员折扣率（如9折输入10）："))
if self.cart.set_member_discount(discount):
print(f"✅ 已设置会员折扣：{discount}%")
except ValueError:
print("❌ 请输入有效的折扣率！")
elif choice == "2":
try:
amount = float(input("优惠券金额（元）："))
if self.cart.set_coupon_discount(amount):
print(f"✅ 已使用优惠券：减{amount}元")
except ValueError:
print("❌ 请输入有效的金额！")
def process_payment(self):
"""处理付款"""
total = self.cart.get_total()
print(f"\n💰 应收金额：¥{total:.2f}")
try:
payment = float(input("收到金额：¥"))
if payment < total:
print("❌ 金额不足！")
return None
change = payment - total
print(f"\n{'='*50}")
print(f"{'💵 交易完成':^50}")
print(f"{'='*50}")
print(f"应收：¥{total:.2f}")
print(f"实收：¥{payment:.2f}")
print(f"找零：¥{change:.2f}")
return {
"total": total,
"payment": payment,
"change": change
}
except ValueError:
print("❌ 请输入有效的金额！")
return None
def print_receipt(self, payment_info):
"""打印小票"""
self.receipt_number += 1
receipt_no = f"{self.receipt_number:04d}"
print(f"\n{'='*60}")
print(f"{'🧾 购物小票':^60}")
print(f"{'='*60}")
print(f"小票号：{receipt_no}")
print(f"日期：2024年1月")
print(f"{'='*60}")
print(f"{'商品':<12} {'单价':>8} {'数量':>6} {'小计':>10}")
print(f"{'-'*60}")
for code, item in self.cart.items.items():
product = item["product"]
quantity = item["quantity"]
line_total = product["price"] * quantity
print(f"{product['name']:<12} ¥{product['price']:>6.2f} ×{quantity:>4} ¥{line_total:>8.2f}")
print(f"{'-'*60}")
print(f"{'小计':>30} ¥{self.cart.get_subtotal():>8.2f}")
if self.cart.member_discount > 0:
saving = self.cart.get_subtotal() * (self.cart.member_discount / 100)
print(f"{'会员折扣':>30} -¥{saving:>8.2f}")
if self.cart.coupon_discount > 0:
print(f"{'优惠券':>30} -¥{self.cart.coupon_discount:>8.2f}")
print(f"{'='*60}")
print(f"{'应付金额':>30} ¥{payment_info['total']:>8.2f}")
print(f"{'实收金额':>30} ¥{payment_info['payment']:>8.2f}")
print(f"{'找零金额':>30} ¥{payment_info['change']:>8.2f}")
print(f"{'='*60}")
print(f"{'感谢光临，欢迎下次惠顾！':^56}")
print(f"{'='*60}")
# 记录交易
transaction = {
"receipt_no": receipt_no,
"items": dict(self.cart.items),
"subtotal": self.cart.get_subtotal(),
"member_discount": self.cart.member_discount,
"coupon_discount": self.cart.coupon_discount,
"total": payment_info["total"],
"payment": payment_info["payment"],
"change": payment_info["change"]
}
self.transaction_history.append(transaction)
self.daily_sales += payment_info["total"]
# 清空购物车
self.cart.clear_cart()
def show_daily_report(self):
"""显示日报表"""
if not self.transaction_history:
print("📊 今日暂无交易记录")
return
print(f"\n{'='*60}")
print(f"{'📊 销售日报表':^60}")
print(f"{'='*60}")
print(f"交易笔数：{len(self.transaction_history)}笔")
print(f"销售总额：¥{self.daily_sales:.2f}")
print(f"\n交易明细：")
for i, trans in enumerate(self.transaction_history, 1):
items_count = len(trans["items"])
print(f" {i}. 小票{trans['receipt_no']} - {items_count}件商品 - ¥{trans['total']:.2f}")
# 运行收银系统
register = CashRegister()
print("🏪 欢迎使用智能收银系统！")
print("=" * 50)
while True:
print("\n请选择操作：")
print("1. 🛒 开始新订单")
print("2. 📊 查看日报表")
print("3. 🚪 下班结账")
choice = input("\n请选择（1-3）：")
if choice == "3":
register.show_daily_report()
print("\n👋 下班了！辛苦了！")
break
elif choice == "2":
register.show_daily_report()
elif choice == "1":
print(f"\n{'='*50}")
print(f"{'🆕 新订单':^50}")
print(f"{'='*50}")
# 显示商品列表
display_products()
# 扫描商品
register.scan_item()
if register.cart.get_items_count() > 0:
# 显示购物车
register.cart.display_cart()
# 应用折扣
register.apply_discounts()
# 显示最终金额
register.cart.display_cart()
# 处理付款
payment_info = register.process_payment()
if payment_info:
# 打印小票
register.print_receipt(payment_info)
else:
print("❌ 购物车为空，取消订单")
else:
print("❌ 请选择1-3！")2.2 促销活动系统
# 促销活动系统
print("\n🎉 促销活动系统")
print("=" * 50)
class PromotionSystem:
"""促销活动系统"""
def __init__(self):
self.active_promotions = []
self.promotion_history = []
def add_buy_x_get_y_free(self, product_code, buy_qty, free_qty):
"""添加买X送Y活动"""
promotion = {
"type": "buy_x_get_y_free",
"product_code": product_code,
"buy_qty": buy_qty,
"free_qty": free_qty,
"description": f"买{buy_qty}送{free_qty}"
}
self.active_promotions.append(promotion)
return True
def add_discount_on_category(self, category, discount_percent, min_amount=0):
"""添加品类折扣"""
promotion = {
"type": "category_discount",
"category": category,
"discount_percent": discount_percent,
"min_amount": min_amount,
"description": f"{category}类{discount_percent}%折扣"
}
self.active_promotions.append(promotion)
return True
def add_full_reduction(self, threshold, reduction):
"""添加满减活动"""
promotion = {
"type": "full_reduction",
"threshold": threshold,
"reduction": reduction,
"description": f"满¥{threshold}减¥{reduction}"
}
self.active_promotions.append(promotion)
return True
def add_time_limit_discount(self, product_code, discount_percent, start_hour, end_hour):
"""添加限时折扣"""
promotion = {
"type": "time_limit",
"product_code": product_code,
"discount_percent": discount_percent,
"start_hour": start_hour,
"end_hour": end_hour,
"description": f"限时{discount_percent}%折扣"
}
self.active_promotions.append(promotion)
return True
def calculate_promotions(self, cart):
"""计算所有活动的优惠"""
savings = []
subtotal = cart.get_subtotal()
for promo in self.active_promotions:
if promo["type"] == "buy_x_get_y_free":
# 买X送Y
code = promo["product_code"]
if code in cart.items:
qty = cart.items[code]["quantity"]
if qty >= promo["buy_qty"]:
free_count = (qty // promo["buy_qty"]) * promo["free_qty"]
product = cart.items[code]["product"]
saving = product["price"] * free_count
savings.append({
"description": f"{product['name']} {promo['description']}",
"amount": saving
})
elif promo["type"] == "category_discount":
# 品类折扣
category = promo["category"]
category_total = 0
for code, item in cart.items.items():
if item["product"]["category"] == category:
category_total += item["product"]["price"] * item["quantity"]
if category_total >= promo["min_amount"]:
saving = category_total * (promo["discount_percent"] / 100)
savings.append({
"description": f"{category}类{promo['discount_percent']}%折扣",
"amount": saving
})
elif promo["type"] == "full_reduction":
# 满减
if subtotal >= promo["threshold"]:
savings.append({
"description": f"满¥{promo['threshold']}减¥{promo['reduction']}",
"amount": promo["reduction"]
})
return savings
def show_active_promotions(self):
"""显示当前活动"""
if not self.active_promotions:
print("📢 当前没有促销活动")
return
print(f"\n{'='*50}")
print(f"{'🎉 当前促销活动':^50}")
print(f"{'='*50}")
for i, promo in enumerate(self.active_promotions, 1):
print(f"{i}. {promo['description']}")
# 促销系统演示
promo_system = PromotionSystem()
print("🎉 促销活动设置：")
print("-" * 40)
# 添加促销活动
promo_system.add_buy_x_get_y_free("003", 2, 1) # 牛奶买2送1
promo_system.add_discount_on_category("零食", 20) # 零食8折
promo_system.add_full_reduction(50, 10) # 满50减10
promo_system.show_active_promotions()
# 测试促销计算
test_cart = ShoppingCart()
test_cart.add_item("003", 3) # 3盒牛奶
test_cart.add_item("007", 2) # 2袋薯片
print("\n📋 测试购物车：")
test_cart.display_cart()
print("\n💰 促销优惠计算：")
savings = promo_system.calculate_promotions(test_cart)
total_saving = 0
for saving in savings:
print(f" 🎉 {saving['description']}：省¥{saving['amount']:.2f}")
total_saving += saving["amount"]
print(f"\n💵 总共节省：¥{total_saving:.2f}")🎯 第三部分：智能收银系统整合
3.1 完整智能收银系统
# 完整智能收银系统
print("\n🏪 智能收银系统 V2.0")
print("=" * 50)
class SmartCashRegister(CashRegister):
"""智能收银系统"""
def __init__(self):
super().__init__()
self.promotion_system = PromotionSystem()
self.members = {} # 会员系统
self.current_member = None
def member_login(self):
"""会员登录"""
print("\n👤 会员登录")
phone = input("请输入手机号：")
if phone in self.members:
member = self.members[phone]
print(f"欢迎回来，{member['name']}！")
print(f"积分：{member['points']}")
self.current_member = member
return member
else:
register = input("未注册，是否注册？（是/否）：")
if register == "是":
name = input("请输入姓名：")
self.members[phone] = {
"name": name,
"phone": phone,
"points": 0,
"level": "普通会员"
}
self.current_member = self.members[phone]
print(f"✅ 注册成功！欢迎{name}！")
return self.members[phone]
else:
return None
def auto_apply_promotions(self):
"""自动应用最优促销方案"""
savings = self.promotion_system.calculate_promotions(self.cart)
total_saving = 0
for saving in savings:
total_saving += saving["amount"]
# 自动应用满减
if total_saving > 0:
self.cart.set_coupon_discount(total_saving)
return savings
def suggest_combo(self):
"""智能推荐搭配"""
if not self.cart.items:
return
suggestions = []
categories_in_cart = set()
for code, item in self.cart.items.items():
categories_in_cart.add(item["product"]["category"])
# 根据已有商品推荐搭配
if "零食" in self.cart.items:
suggestions.append("推荐搭配：可乐（¥3.00）- 零食好搭档！")
if "水果" in categories_in_cart:
suggestions.append("推荐搭配：酸奶（即将上架）- 水果沙拉必备！")
if "食品" in categories_in_cart:
suggestions.append("推荐搭配：饮料 - 用餐好伴侣！")
if suggestions:
print(f"\n💡 为您推荐：")
for s in suggestions:
print(f" {s}")
def checkout_with_points(self):
"""使用积分抵扣"""
if not self.current_member:
return False
points = self.current_member["points"]
if points < 100:
print(f"💡 当前积分：{points}（满100积分可用）")
return False
use_points = input(f"当前积分{points}，是否使用积分抵扣？（是/否）：")
if use_points == "是":
max_deduct = points // 100 * 5 # 每100积分抵5元
total = self.cart.get_total()
deduct = min(max_deduct, total)
self.cart.set_coupon_discount(deduct)
self.current_member["points"] -= deduct * 20 # 每元消耗20积分
print(f"✅ 使用积分抵扣¥{deduct:.2f}")
return True
return False
def earn_points(self, amount):
"""赚取积分"""
if self.current_member:
earned = int(amount)
self.current_member["points"] += earned
print(f"⭐ 获得{earned}积分！当前积分：{self.current_member['points']}")
def process_smart_checkout(self):
"""智能结账流程"""
print(f"\n{'='*50}")
print(f"{'🤖 智能结账':^50}")
print(f"{'='*50}")
# 显示购物车
self.cart.display_cart()
# 智能推荐
self.suggest_combo()
# 自动应用促销
print("\n📢 正在计算优惠...")
savings = self.auto_apply_promotions()
if savings:
print("🎉 已为您自动应用以下优惠：")
for saving in savings:
print(f" ✅ {saving['description']}：省¥{saving['amount']:.2f}")
# 会员积分
if self.current_member:
self.checkout_with_points()
# 显示最终金额
self.cart.display_cart()
# 处理付款
payment_info = self.process_payment()
if payment_info:
# 赚取积分
self.earn_points(payment_info["total"])
# 打印小票
self.print_receipt(payment_info)
# 初始化促销活动
def init_promotions(system):
"""初始化促销活动"""
system.promotion_system.add_buy_x_get_y_free("003", 2, 1) # 牛奶买2送1
system.promotion_system.add_discount_on_category("零食", 20) # 零食8折
system.promotion_system.add_full_reduction(50, 10) # 满50减10
system.promotion_system.add_full_reduction(100, 25) # 满100减25
# 运行智能收银系统
smart_register = SmartCashRegister()
init_promotions(smart_register)
print("🏪 欢迎使用智能收银系统 V2.0！")
print("=" * 50)
while True:
print("\n请选择操作：")
print("1. 🛒 开始新订单")
print("2. 👤 会员登录")
print("3. 🎉 查看促销活动")
print("4. 📊 查看日报表")
print("5. 🚪 下班结账")
choice = input("\n请选择（1-5）：")
if choice == "5":
smart_register.show_daily_report()
print("\n👋 下班了！辛苦了！")
break
elif choice == "4":
smart_register.show_daily_report()
elif choice == "3":
smart_register.promotion_system.show_active_promotions()
elif choice == "2":
smart_register.member_login()
elif choice == "1":
print(f"\n{'='*50}")
print(f"{'🆕 新订单':^50}")
print(f"{'='*50}")
# 显示商品
display_products()
# 扫描商品
smart_register.scan_item()
if smart_register.cart.get_items_count() > 0:
# 智能结账
smart_register.process_smart_checkout()
else:
print("❌ 购物车为空，取消订单")
else:
print("❌ 请选择1-5！")3.2 收银系统管理后台
# 收银系统管理后台
print("\n⚙️ 收银系统管理后台")
print("=" * 50)
class ManagementConsole:
"""管理后台"""
def __init__(self, cash_register):
self.register = cash_register
self.admin_password = "admin123"
def admin_login(self):
"""管理员登录"""
password = input("请输入管理员密码：")
return password == self.admin_password
def manage_products(self):
"""管理商品"""
print(f"\n{'='*50}")
print(f"{'📦 商品管理':^50}")
print(f"{'='*50}")
while True:
print("\n请选择操作：")
print("1. 📋 查看所有商品")
print("2. ➕ 添加商品")
print("3. ✏️ 修改商品价格")
print("4. ❌ 下架商品")
print("5. 🔙 返回")
choice = input("请选择（1-5）：")
if choice == "5":
break
elif choice == "1":
display_products()
elif choice == "2":
code = input("商品编号：")
name = input("商品名称：")
price = float(input("单价："))
unit = input("单位：")
category = input("类别：")
products[code] = {
"name": name,
"price": price,
"unit": unit,
"category": category
}
print(f"✅ 已添加商品：{name}")
elif choice == "3":
code = input("商品编号：")
if code in products:
new_price = float(input("新价格："))
old_price = products[code]["price"]
products[code]["price"] = new_price
print(f"✅ {products[code]['name']}：¥{old_price} → ¥{new_price}")
else:
print("❌ 商品不存在！")
elif choice == "4":
code = input("商品编号：")
if code in products:
confirm = input(f"确认下架 {products[code]['name']}？（是/否）：")
if confirm == "是":
del products[code]
print("✅ 已下架")
else:
print("❌ 商品不存在！")
def manage_promotions(self):
"""管理促销活动"""
print(f"\n{'='*50}")
print(f"{'🎉 促销管理':^50}")
print(f"{'='*50}")
while True:
print("\n请选择操作：")
print("1. 📋 查看当前活动")
print("2. ➕ 添加买赠活动")
print("3. ➕ 添加品类折扣")
print("4. ➕ 添加满减活动")
print("5. ❌ 清除所有活动")
print("6. 🔙 返回")
choice = input("请选择（1-6）：")
if choice == "6":
break
elif choice == "1":
self.register.promotion_system.show_active_promotions()
elif choice == "2":
code = input("商品编号：")
buy = int(input("购买数量："))
free = int(input("赠送数量："))
self.register.promotion_system.add_buy_x_get_y_free(code, buy, free)
print("✅ 已添加买赠活动")
elif choice == "3":
category = input("商品类别：")
discount = float(input("折扣率（如8折输入20）："))
min_amount = float(input("最低消费金额（0为不限）："))
self.register.promotion_system.add_discount_on_category(category, discount, min_amount)
print("✅ 已添加品类折扣")
elif choice == "4":
threshold = float(input("满多少元："))
reduction = float(input("减多少元："))
self.register.promotion_system.add_full_reduction(threshold, reduction)
print("✅ 已添加满减活动")
elif choice == "5":
confirm = input("确认清除所有活动？（是/否）：")
if confirm == "是":
self.register.promotion_system.active_promotions.clear()
print("✅ 已清除所有活动")
def view_transactions(self):
"""查看交易记录"""
print(f"\n{'='*50}")
print(f"{'📊 交易记录':^50}")
print(f"{'='*50}")
if not self.register.transaction_history:
print("暂无交易记录")
return
for i, trans in enumerate(self.register.transaction_history, 1):
print(f"\n交易{i}：")
print(f" 小票号：{trans['receipt_no']}")
print(f" 商品数：{len(trans['items'])}种")
print(f" 小计：¥{trans['subtotal']:.2f}")
if trans['member_discount'] > 0:
print(f" 会员折扣：{trans['member_discount']}%")
if trans['coupon_discount'] > 0:
print(f" 优惠券：-¥{trans['coupon_discount']:.2f}")
print(f" 实收：¥{trans['total']:.2f}")
print(f" 找零：¥{trans['change']:.2f}")
# 管理后台入口
console = ManagementConsole(smart_register)
print("⚙️ 收银系统管理后台")
print("=" * 50)
if console.admin_login():
print("✅ 登录成功！")
while True:
print("\n请选择管理功能：")
print("1. 📦 商品管理")
print("2. 🎉 促销管理")
print("3. 📊 交易记录")
print("4. 🔙 退出管理")
choice = input("请选择（1-4）：")
if choice == "4":
print("👋 管理后台已退出")
break
elif choice == "1":
console.manage_products()
elif choice == "2":
console.manage_promotions()
elif choice == "3":
console.view_transactions()
else:
print("❌ 请选择1-4！")
else:
print("❌ 密码错误！")📅 第三阶段总结
🎯 本阶段学习成果
第21-30课：逻辑思维培养
| 课程 | 知识点 | 项目实践 |
|------|--------|---------|
| 第21课 | 单分支if语句 | 条件判断入门 |
| 第22课 | if-else语句 | 二选一决策 |
| 第23课 | if-elif-else多分支 | 多选一迷宫 |
| 第24课 | 条件嵌套 | 俄罗斯套娃逻辑 |
| 第25课 | 综合应用 | 成绩评定系统 |
| 第26课 | 错误处理 | 计算器升级版 |
| 第27课 | 多条件判断 | 年龄判断机 |
| 第28课 | 复合条件 | 闰年判断器 |
| 第29课 | 综合项目 | 猜拳游戏 |
| 第30课 | 终极项目 | 智能收银系统 |
🏆 核心能力提升
- 逻辑思维：掌握了条件判断的完整体系
- 问题分解：学会将复杂问题拆解为简单条件
- 系统设计：能够设计完整的应用程序
- 用户体验：注重交互设计和错误处理
- 工程实践：养成了良好的编程习惯
🚀 下一阶段展望
第四阶段：循环与数据结构
- 学习for循环和while循环
- 掌握列表、字典等数据结构
- 制作批量数据处理程序
- 开发更复杂的应用系统
💬 给家长的话
亲爱的家长：
恭喜！孩子完成了第三阶段的学习，并成功制作了智能收银系统这个综合性项目！
孩子在本阶段学会了：
- ✅ 完整的条件判断体系
- ✅ 多分支和嵌套逻辑
- ✅ 错误处理和异常捕获
- ✅ 系统化程序设计
- ✅ 综合项目管理能力
智能收银系统的教育价值：
| 能力 | 项目应用 | 现实意义 |
|------|---------|---------|
| 逻辑思维 | 折扣计算逻辑 | 分析决策 |
| 数学应用 | 金额计算找零 | 实用数学 |
| 系统设计 | 完整收银流程 | 工程思维 |
| 用户体验 | 友好的交互 | 产品思维 |
| 商业意识 | 促销活动设计 | 商业思维 |
您可以这样做：
- 角色扮演：和孩子玩超市收银游戏
- 实际应用：用程序管理家庭开支
- 创意扩展：一起设计新功能
- 职业启蒙：了解收银系统的工作原理
温馨提示：
- 第三阶段是编程思维的重要转折点
- 条件判断是编程的核心能力
- 鼓励孩子用编程解决实际问题
- 为下一阶段学习做好准备
🏆 第三阶段成就
完成了第三阶段的学习，你：
🧠 培养了逻辑思维
🔧 掌握了条件判断
🏪 制作了收银系统
🎮 开发了猜拳游戏
📊 完成了数据分析
挑战任务：
- 为收银系统添加更多支付方式
- 制作库存管理功能
- 添加数据可视化图表
- 实现多门店管理
🌟 编程心法
⬅️ 上一课下一课 ➡️