drawing.cs

北大青鸟-Cs学生用书-教师用书实例源代码.rar

using System;

namespace Example_1
{
	/// <summary>
	/// 此程序演示继承过程中 override 和 virtual 关键字的用法
	/// </summary>
	/// 
	//基类

	public class DrawObject
	{
		public virtual void Draw()
		{
			Console.WriteLine("在基类中绘制对象。");
		}
	}

	//派生类包含重写方法
	public class DrawLine : DrawObject
	{
		public override void Draw()
		{
			Console.WriteLine("我要画一条直线。");
		}
	}

	public class DrawCircle : DrawObject
	{
		public override void Draw()
		{
			Console.WriteLine("我要画一个圆。");
		}
	}

	public class DrawRectangle : DrawObject
	{
		public override void Draw()
		{
			Console.WriteLine("我要画一个矩形。");
		}
	}

    
	class Class1
	{
		/// <summary>
		/// 应用程序的主入口点。
		/// </summary>
		[STAThread]
		static void Main(string[] args)
		{
			//
			DrawObject[] ObjD = new DrawObject[4];

			ObjD[0] = new DrawLine();
			ObjD[1] = new DrawCircle();
			ObjD[2] = new DrawRectangle();
			ObjD[3] = new DrawObject();

			foreach (DrawObject drawObj in ObjD)
			{
				drawObj.Draw();
			}

		}
	}
}