score = 85
print("成绩及格")

score = 85

if score >= 60:
    print("成绩及格")
else:
    print("成绩不及格")

if 条件:
    执行的代码

age = 20

if age >= 18:
    print("你已经成年了")
    print("可以考驾照了")

age = 16

if age >= 18:
    print("你已经成年了")  # 不会执行

print("程序继续运行")  # 会执行

score = 55

if score >= 60:
    print("及格")
else:
    print("不及格")

score = 85

if score >= 90:
    print("优秀")
elif score >= 80:
    print("良好")
elif score >= 60:
    print("及格")
else:
    print("不及格")

age = 20
has_id = True

if age >= 18:
    if has_id:
        print("可以进入网吧")
    else:
        print("请出示身份证")
else:
    print("未成年人禁止入内")

age = 20
has_id = True

if age >= 18 and has_id:
    print("可以进入网吧")
elif age >= 18 and not has_id:
    print("请出示身份证")
else:
    print("未成年人禁止入内")

score = 85

# 传统写法
if score >= 60 and score < 90:
    print("成绩良好")

# 链式比较（推荐）
if 60 <= score < 90:
    print("成绩良好")

# ❌ 错误
if score >= 60
    print("及格")

# ✅ 正确
if score >= 60:
    print("及格")

# ❌ 错误：缩进不一致
if score >= 60:
    print("及格")
      print("恭喜")  # 缩进多了

# ✅ 正确
if score >= 60:
    print("及格")
    print("恭喜")

# ❌ 错误
if score = 60:  # SyntaxError
    print("及格")

# ✅ 正确
if score == 60:
    print("及格")

name = input("请输入你的姓名：")
print(f"你好，{name}！")

age = input("请输入你的年龄：")
print(type(age))  # <class 'str'>

age = input("请输入你的年龄：")
age = int(age)  # 转换为整数

if age >= 18:
    print("你已经成年了")

# 转换为整数
age = int(input("请输入你的年龄："))

# 转换为浮点数
price = float(input("请输入价格："))

age = int(input("请输入你的年龄："))
# 如果用户输入 "abc"，会报错：ValueError: invalid literal for int()

scores = [90, 85, 92, 88, 95]

print(scores[0])
print(scores[1])
print(scores[2])
print(scores[3])
print(scores[4])

scores = [90, 85, 92, 88, 95]

for score in scores:
    print(score)

# 打印 0 到 4
for i in range(5):
    print(i)  # 0, 1, 2, 3, 4

# 打印 1 到 5
for i in range(1, 6):
    print(i)  # 1, 2, 3, 4, 5

# 打印 0 到 10，步长为 2
for i in range(0, 11, 2):
    print(i)  # 0, 2, 4, 6, 8, 10

# 遍历列表
fruits = ["apple", "banana", "cherry"]
for fruit in fruits:
    print(fruit)

# 遍历字典的键
student = {"name": "张三", "age": 25}
for key in student:
    print(key, student[key])

# 遍历字典的键值对
for key, value in student.items():
    print(key, value)

fruits = ["apple", "banana", "cherry"]

for index, fruit in enumerate(fruits):
    print(f"{index}: {fruit}")
# 输出：
# 0: apple
# 1: banana
# 2: cherry

names = ["张三", "李四", "王五"]
ages = [25, 30, 28]

for name, age in zip(names, ages):
    print(f"{name} 今年 {age} 岁")

count = 0

while count < 5:
    print(count)
    count += 1

while True:
    user_input = input("请输入 'q' 退出：")
    if user_input == "q":
        break
    print(f"你输入了：{user_input}")

for i in range(10):
    if i == 5:
        break
    print(i)  # 输出 0, 1, 2, 3, 4

for i in range(5):
    if i == 2:
        continue
    print(i)  # 输出 0, 1, 3, 4

status = "success"

if status == "success":
    print("操作成功")
elif status == "error":
    print("操作失败")
elif status == "pending":
    print("等待中")
else:
    print("未知状态")

status = "success"

match status:
    case "success":
        print("操作成功")
    case "error":
        print("操作失败")
    case "pending":
        print("等待中")
    case _:
        print("未知状态")

day = "Saturday"

match day:
    case "Saturday" | "Sunday":
        print("周末")
    case "Monday" | "Tuesday" | "Wednesday" | "Thursday" | "Friday":
        print("工作日")
    case _:
        print("无效的日期")

score = 85

match score:
    case s if s >= 90:
        print("优秀")
    case s if s >= 60:
        print("及格")
    case _:
        print("不及格")

import random

# 生成 1-100 的随机数
secret = random.randint(1, 100)
attempts = 0

print("欢迎来到猜数字游戏！")
print("我想了一个 1-100 之间的数字，你能猜到吗？")

while True:
    guess = int(input("请输入你的猜测："))
    attempts += 1

    if guess < secret:
        print("太小了！")
    elif guess > secret:
        print("太大了！")
    else:
        print(f"恭喜你猜对了！你用了 {attempts} 次")
        break