• เข้าใจว่าตัวแปรคืออะไร
• ชนิดของตัวแปรคืออะไร
• ตัวดำเนินการคืออะไร

using System;

class Booleans
{
    public static void Main()
    {
        bool content = true;
        bool noContent = false;

        Console.WriteLine("It is {0} that C# Station provides C# programming language content.", content);
        Console.WriteLine("The statement above is not {0}.", noContent);
    }
}

It is True that C# Station provides C# programming language content.
The statement above is not False. 

17    preIncrement = ++unary;

 20   preDecrement = --unary; 

23    postDecrement = unary--;

26    postIncrement = unary++;

31        positive = -postIncrement;
32        Console.WriteLine("Positive: {0}", positive);
33
34        negative = +postIncrement;
35        Console.WriteLine("Negative: {0}", negative);

37       bitNot = 0;
38       bitNot = (sbyte)(~bitNot);
39       Console.WriteLine("Bitwise Not: {0}", bitNot);

41      logNot = false;
42      logNot = !logNot;
43      Console.WriteLine("Logical Not: {0}", logNot);

pre-Increment: 1
pre-Decrement 0
Post-Decrement: 0
Post-Increment: -1
Final Value of Unary: 0
Positive: 1
Negative: -1
Bitwise Not: -1
Logical Not: true 

x+y: 12
x-y: 2
x*y: 35
x/y: 1
x/y: 1.4
x%y: 2
result+=x: 9

// Hello1.cs
public class Hello1
{
   public static void Main()
   {
      System.Console.WriteLine("Hello, World!");
   }
}

Hello, World!

// Hello2.cs
using System;

public class Hello2
{
   public static void Main()
   {
      Console.WriteLine("Hello, World!");
   }
}

// Hello3.cs
// arguments: A B C D
using System;

public class Hello3
{
   public static void Main(string[] args)
   {
      Console.WriteLine("Hello, World!");
      Console.WriteLine("You entered the following {0} command line arguments:",
         args.Length );
      for (int i=0; i < args.Length; i++)
      {
         Console.WriteLine("{0}", args[i]); 
      }
   }
}

Hello, World!
You entered the following 4 command line arguments:
A
B
C
D

// Hello4.cs
using System;

public class Hello4
{
   public static int Main(string[] args)
   {
      Console.WriteLine("Hello, World!");
      return 0;
   }
}

Hello, World!

using System;

   class HelloWorld
   {
      static void Main(string[] args)
      {
         Console.WriteLine("Hello World");
         Console.ReadKey();
      }
   }

• java (or java.exe)
• javac (or javac.exe)

javac MyFirstClass.java

java MyFirstClass.class

java MyFirstClass

public class Arguments {
    public static void main(String[] args) {
        for (int i = 0; i < args.length; i++) {
            System.out.println(args[i]);
        }
    }
}

javac Arguments.java
java Arguments arg0 arg1 arg2

class Point {
    int x;
    int y;
}

Point p = new Point();

class Point {
    int x;
    int y;
    Point(int x, int y) {
        this.x = x;
        this.y = y;
    }

class Point {
    int x;
    int y;
    Point() {
        this(0, 0);
    }
    Point(int x, int y) {
        this.x = x;
        this.y = y;
    }

p.x = 3;
p.y = 6;

Methods

class Point {
    ... // code ของเราก่อนหน้านี้
    void printPoint() {
        System.out.println("(" + x + "," + y + ")");
    }
    Point center(Point other) {
        // เราคืนค่าจุดศูนย์กลางของจุดนี้และจุดอื่น
        return new Point((x + other.x) / 2, (y + other.y) / 2);
    }

Public and Private

class Point 
    private double x;
    private double y;
    public Point(double x, double y) {
        this.x = x;
        this.y = y;
    }
    public void print() {
        System.out.println("(" + x + "," + y + ")");
    }
    // สร้างตรงนี้
}

public class Main {
    public static void main(String[] args) {
        Point p = new Point(32, 32);
        for (int i = 0; i < 5; i++) {
            p.scale();
            p.print();
        }
    }
}