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0727 综合作业#

来源：D:\study\C#1\stu0727\0727作业

作业 1：抽象类 + 虚方法 — 动物叫声#

abstract class Animal
{
    public string Name { get; set; }
    public int MaxAge { get; set; }
    int nowage;

    // 属性 set 中包含验证逻辑
    public int NowAge
    {
        get => nowage;
        set
        {
            if (value > MaxAge)
                throw new Exception("年龄超出最大值");
            nowage = value;
        }
    }
    public string Sex { get; set; }

    // 抽象方法 — 子类必须实现
    public abstract void Speak();

    public Random r = new Random();

    public Animal(int maxage)
    {
        MaxAge = maxage;
        NowAge = r.Next(0, MaxAge + 1);  // 随机年龄
    }
}

class Dog : Animal
{
    public Dog() : this(20) { }
    public Dog(int max) : base(max) { }

    public override void Speak()
    {
        Console.WriteLine("汪汪汪");
    }
}

class Cat : Animal
{
    public Cat() : this(10) { }
    public Cat(int max) : base(max) { }

    public override void Speak()
    {
        Console.WriteLine("喵喵喵");
    }
}

使用：

Dog dog = new Dog(20);
Console.WriteLine(dog.NowAge + "岁");
dog.Speak();    // → "汪汪汪"

Cat cat = new Cat(20);
cat.Speak();    // → "喵喵喵"

作业 2：构造函数重载 — 面积计算#

class Calculate
{
    int Length { get; set; }
    int Wide { get; set; }
    int High { get; set; }
    public int S { get; set; }

    // 无参构造函数
    public Calculate() { }

    // 正方形：1 个参数
    public Calculate(int length)
    {
        Length = length;
        S = Length * Length;
    }

    // 长方形：2 个参数
    public Calculate(int length, int wide)
    {
        Length = length;
        Wide = wide;
        S = Length * Wide;
    }

    // 梯形：3 个参数
    public Calculate(int length, int wide, int high)
    {
        Length = length;
        Wide = wide;
        High = high;
        S = (Length + Wide) * High / 2;
    }
}

使用：

Console.WriteLine("正方形：" + new Calculate(10).S);          // → 100
Console.WriteLine("长方形：" + new Calculate(10, 5).S);       // → 50
Console.WriteLine("梯形：" + new Calculate(10, 100, 70).S);   // → 3850

作业 3：抽象类 + 多态 — 借阅系统#

abstract class Account
{
    public string Acc { get; set; }
    public string Password { get; set; }
    public Account(string acc, string passwd)
    {
        Acc = acc;
        Password = passwd;
    }
    public abstract string pay(decimal money);
}

class Weixin : Account
{
    public Weixin(string acc, string passwd) : base(acc, passwd) { }
    public override string pay(decimal money)
    {
        return $"微信支付+{money} 元";
    }
}

class Ali : Account
{
    public Ali(string acc, string passwd) : base(acc, passwd) { }
    public override string pay(decimal money)
    {
        return $"支付宝支付+{money} 元";
    }
}

作业 4：多层抽象继承 — 图书馆借阅#

class Library
{
    public string StuName { get; set; }
    int StuBook { get; set; }
    public Library(string stuname)
    {
        StuName = stuname;
    }
}

abstract class Book : Library
{
    public Book(string name) : base(name) { }
    public abstract void Borrow(int book);
}

class Benke : Book    // 本科生 — 最多借 5 本
{
    public Benke(string name) : base(name) { }
    public override void Borrow(int book)
    {
        if (book > 5)
            Console.WriteLine("超出本科生借阅量");
        else
            Console.WriteLine($"你还可以借书{5 - book}本");
    }
}

class Shuoshi : Book  // 硕士生 — 最多借 10 本
{
    public Shuoshi(string name) : base(name) { }
    public override void Borrow(int book)
    {
        if (book > 10)
            Console.WriteLine("超出硕士生借阅量");
        else
            Console.WriteLine($"你还可以借书{10 - book}本");
    }
}

class Boshi : Book    // 博士生 — 最多借 15 本
{
    public Boshi(string name) : base(name) { }
    public override void Borrow(int book)
    {
        if (book > 15)
            Console.WriteLine("超出博士生借阅量");
        else
            Console.WriteLine($"你还可以借书{15 - book}本");
    }
}

使用：

Benke benke = new Benke("张三");
benke.Borrow(4);    // → "你还可以借书1本"

Shuoshi shuoshi = new Shuoshi("李四");
shuoshi.Borrow(5);  // → "你还可以借书5本"

Boshi boshi = new Boshi("王五");
boshi.Borrow(10);   // → "你还可以借书5本"

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