C# 與物件導向的繼承 (Inheritance)

基礎篇

C＃ 簡介

開發環境

變數與運算

流程控制

陣列

函數

物件

例外處理

函式庫篇

檔案處理

資料結構

正規表達式

Thread

應用篇

視窗程式

媒體影音

網路程式

遊戲程式

手機程式

資料庫

雲端運算

特殊功能

委派

擴展方法

序列化

LinQ

WPF

網路資源

教學影片

投影片

教學文章

軟體下載

考題解答

101習題

範例一：矩形、圓形繼承形狀 (Shape)

using System;

class Shape
{
    public virtual double area() { return 0.0; }
}

class Rectangle : Shape
{
    double width, height;

    public Rectangle(double w, double h)
    {
        width = w;
        height = h;
    }

    public override double area()
    {
        return width * height;
    }
}

class Circle : Shape
{
    double r;

    public Circle(double r)
    {
        this.r = r;
    }

    public override double area()
    {
        return 3.1416 * r * r;
    }
}

class Test
{
    public static void Main(string[] args)
    {
        Shape s = new Shape();
        Console.WriteLine("s.area() = " + s.area());

        Rectangle r = new Rectangle(5.0, 8.0);
        Console.WriteLine("r.area() = " + r.area());

        Circle c = new Circle(2);
        Console.WriteLine("c.area() = " + c.area());
    }
}

執行結果：

s.area() = 0
r.area() = 40
c.area() = 12.5664

範例二：加入厚度與體積函數 (在子物件使用父物件的欄位)

執行結果

s.area() = 0
r.area() = 40
r.volume() = 80
c.area() = 12.5664
c.volume() = 37.6992
c.volume() = 62.832

程式碼

using System;

class Shape
{
    public double thick;
    public virtual double area() { return 0.0; }
}

class Rectangle : Shape
{
    double width, height;

    public Rectangle(double w, double h)
    {
        width = w;
        height = h;
        thick = 2.0;
    }

    public override double area()
    {
        return width * height;
    }

    public double volume()
    {
        return width * height * thick;
    }
}

class Circle : Shape
{
    double r;

    public Circle(double r)
    {
        this.r = r;
        thick = 3.0;
    }

    public override double area()
    {
        return 3.1416 * r * r;
    }

    public double volume()
    {
        return area() * thick;
    }
}

class Test
{
    public static void Main(string[] args)
    {
        Shape s = new Shape();
        Console.WriteLine("s.area() = " + s.area());

        Rectangle r = new Rectangle(5.0, 8.0);
        Console.WriteLine("r.area() = " + r.area());
        Console.WriteLine("r.volume() = " + r.volume());

        Circle c = new Circle(2);
        Console.WriteLine("c.area() = " + c.area());
        Console.WriteLine("c.volume() = " + c.volume());
        c.thick = 5;
        Console.WriteLine("c.volume() = " + c.volume());
    }
}

範例三：將 volume() 函數提到 Shape 物件中

using System;

class Shape
{
    public double thick;
    public virtual double area() { return 0.0; }
    public double volume()
    {
        return area() * thick;
    }
}

class Rectangle : Shape
{
    double width, height;

    public Rectangle(double w, double h)
    {
        width = w;
        height = h;
        thick = 2.0;
    }

    public override double area()
    {
        return width * height;
    }
}

class Circle : Shape
{
    double r;

    public Circle(double r)
    {
        this.r = r;
        thick = 3.0;
    }

    public override double area()
    {
        return 3.1416 * r * r;
    }
}

class Test
{
    public static void Main(string[] args)
    {
        Shape s = new Shape();
        Console.WriteLine("s.area() = " + s.area());

        Rectangle r = new Rectangle(5.0, 8.0);
        Console.WriteLine("r.area() = " + r.area());
        Console.WriteLine("r.volume() = " + r.volume());

        Circle c = new Circle(2);
        Console.WriteLine("c.area() = " + c.area());
        Console.WriteLine("c.volume() = " + c.volume());
        c.thick = 5;
        Console.WriteLine("c.volume() = " + c.volume());
    }
}
page revision: 5, last edited: 09 Oct 2012 03:40
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