c#基本语法解释备忘

using System;                      //it means it's going to use System's method, here is Console.WriteLine(),
namespace RectangleApplication　　　//namespace
{
    class Rectangle　　　　　　　　　　//class 
    {
        // 成员变量
        double length;　　　　　　　　//double is a type of data structures 
        double width;
        public void Acceptdetails()
        {
            length = 4.5;    
            width = 3.5;
        }
        public double GetArea()
        {
            return length * width;
        }
        public void Display()
        {
            Console.WriteLine("Length: {0}", length);   //print length.
            Console.WriteLine("Width: {0}", width);
            Console.WriteLine("Area: {0}", GetArea());
        }
    }
    
    class ExecuteRectangle
    {
        static void Main(string[] args)  //static: no need to work in a object reference, void:means no return, Main:this is the main function ,one class one Main function only
　　　　　　　　　　　　　　　　　　　　　　　　　//string[] means the type of parameter , args means you can decide if you need to fill it in.　　
        {
            Rectangle r = new Rectangle();   //must do it, because another class can only call method of the other class only if it's an object reference, 
　　　　　　　　　　　　　　　　　　　　　　　　　　　　why? just assume this,you have a house design drawing,but you can not live in,you need to build a house and then you can live in it.
            r.Acceptdetails();     //call Acceptdetails() method of r object reference
            r.Display();　　　　　　　//call Display() method of r object reference
            Console.ReadLine();　　　//this will wait you press a button an then continue
        }
    }
}　

Here is a demo that i wrote.
 using System;

namespace RectangleApplication

{

    class Rectangle

    {

        public string length = "wuxian";   // public means it's gettable by outside of class, relatively, private means it's only gettable within class;
　　 }

    static void Main(string[] args)   //if you do not want make a 'instance' to run this method, static is a must. 

        {

            Rectangle r = new Rectangle();

            string x = r.length;

            Console.WriteLine(x);

        }

    }

}