C#学习进阶Hello World的17种写法代码分享

c# hello world写法入门:

1. 初学者

public class helloworld
{
    public static void main()
    {
        system.console.writeline("hello world");
    }
}

2. 改进的hello world

using system;

public class helloworld
{
    public static void main()
    {
        console.writeline("hello world");
    }
}

 3. 命令行形式

 

 using system;

public class helloworld
{
    public static void main(string[] args)
    {
        console.writeline(args[0]);
    }
}
 

 4. 构造函数

 

 using system;

public class helloworld
{
    public helloworld()
    {
        console.writeline("hello world");
    }

    public static void main()
    {
        helloworld hw = new helloworld();
    }
}
 

 c# hello world写法进阶:

 5. 面向对象

using system;

public class helloworld
{
    public void helloworld()
    {
        console.writeline("hello world");
    }

    public static void main()
    {
        helloworld hw = new helloworld();
        hw.helloworld();
    }
}

6. 从其他类

using system;
public class helloworld
{
    public static void main()
    {
        helloworldhelperclass hwh = new helloworldhelperclass();
        hwh.writehelloworld();
    }
}

public class helloworldhelperclass
{
    public void writehelloworld()
    {
        console.writeline("hello world");
    }
}

7. 继承

abstract class helloworldbase
{
    public abstract void writehelloworld();
}
class helloworld : helloworldbase
{
    public override void writehelloworld()
    {
        console.writeline("hello world");
    }
}
class helloworldimp
{
    static void main()
    {
        helloworldbase hwb = helloworld;
        helloworldbase.writehelloworld();
    }
}

8. 静态构造函数

using system;
public class helloworld
{
    private static string strhelloworld;

    static helloworld()
    {
        strhelloworld = "hello world";
    }
    void writehelloworld()
    {
        console.writeline(strhelloworld);
    }

    public static void main()
    {
        helloworld hw = new helloworld();
        hw.writehelloworld();
    }
}

9. 异常处理

using system;

public class helloworld
{
    public static void main(string[] args)
    {
        try
        {
            console.writeline(args[0]);
        }
        catch (indexoutofrangeexception e)
        {
            console.writeline(e.tostring());
        }
    }
}

10. 名字空间

using system;

namespace hellolibrary
{
    public class hellomessage
    {
        public string message
        {
            get
            {
                return "hello, world!!!";
            }
        }
    }
}
//------  
using system;  
using hellolibrary;

namespace helloapplication
{
    class helloapp
    {

        public static void main(string[] args)
        {
            hellomessage m = new hellomessage();
        }
    }
}

11. 属性

using system;
public class helloworld
{
    public string strhelloworld
    {
        get
        {
            return "hello world";
        }
    }

    public static void main()
    {
        helloworld hw = new helloworld();
        console.writeline(cs.strhelloworld);
    }
}

12. 代理

using system;
class helloworld
{
    static void writehelloworld()
    {
        console.writeline("helloworld");
    }
    static void main()
    {
        simpledelegate d = new simpledelegate(writehelloworld);
        d();
    }
}

13. 使用属性

#define debugging

using system;
using system.diagnostics;

public class helloworld : attribute
{
    [conditional("debugging")]
    public void writehelloworld()
    {
        console.writeline("hello world");
    }

    public static void main()
    {
        helloworld hw = new helloworld();
        hw.writehelloworld();
    }
}

14. 接口

using system;

interface ihelloworld
{
    void writehelloworld();
}

public class helloworld : ihelloworld
{
    public void writehelloworld()
    {
        console.writeline("hello world");
    }

    public static void main()
    {
        helloworld hw = new helloworld();

        hw.writehelloworld();
    }
}

c# hello world的特别写法:

15. 动态hello world

using system;  
using system.reflection;

namespace helloworldns
{
    public class helloworld
    {
        public string writehelloworld()
        {
            return "helloworld";
        }

        public static void main(string[] args)
        {
            type hw = type.gettype(args[0]);
            // instantiating a class dynamically 
            object[] nctorparams = new object[] { };
            object nobj = activator.createinstance(hw, nctorparams);//, nctorparams); 
            // invoking a method 
            object[] nmthdparams = new object[] { };
            string strhelloworld = (string)hw.invokemember("writehelloworld", bindingflags.default | bindingflags.invokemethod, null, nobj, nmthdparams);
            console.writeline(strhelloworld);
        }
    }
}

16. 不安全代码hello world

using system;

public class helloworld
{
    unsafe public void writehelloworld(char[] chrarray)
    {
        fixed (char* parr = chrarray)
        {
            char* pch = parr;
            for (int i = 0; i < chrarray.length; i++)
                console.write(*(pch + i));
        }
    }

    public static void main()
    {
        helloworld hw = new helloworld();
        char[] chrhelloworld = new char[] { 'h', 'e', 'l', 'l', 'o', ' ', 'w', 'o', 'r', 'l', 'd' };
        hw.writehelloworld(chrhelloworld);
    }
}

17. 使用interopservices

using system;
using system.runtime.interopservices;

class class1
{
    [dllimport("kernel32")]
    private static extern int beep(int dwfreq, int dwduration);

    static void main(string[] args)
    {
        console.writeline("hello world");
        beep(1000, 2000);
    }
}