в 15:31, 26 мая 2010

2010-05-26T15:31:53Z

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2010-05-26T12:16:01Z

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==A class with method and member variables==

<source lang="csharp">using System;
class Employee
{
// constructor
public Employee(string name, float billingRate)
{
this.name = name;
this.billingRate = billingRate;
}
// figure out the charge based on Employee"s rate
public float CalculateCharge(float hours)
{
return(hours * billingRate);
}
// return the name of this type
public string TypeName()
{
return("Employee");
}

private string name;
protected float billingRate;
}
class MainClass
{
public static void Main()
{
Employee Employee = new Employee("A", 21.20F);
Console.WriteLine("Name is: {0}", Employee.TypeName());
}
}</source>
<pre class=codeResult>Name is: Employee</pre>

==Add a method to access the field variables==

<source lang="csharp">using System;

class Building {
public int area;
public int occupants;

public void areaPerPerson() {
Console.WriteLine("Display the area per person.");
Console.WriteLine(" " + area / occupants +
" area per person");
}
}

class BuildingDemo {
public static void Main() {
Building house = new Building();
Building office = new Building();

house.occupants = 4;
house.area = 2500;

// assign values to fields in office
office.occupants = 25;
office.area = 4200;

Console.WriteLine("house has:\n " +
house.occupants + " occupants\n " +
house.area + " total area");
house.areaPerPerson();

Console.WriteLine();

Console.WriteLine("office has:\n " +
office.occupants + " occupants\n " +
office.area + " total area");
office.areaPerPerson();
}
}</source>
<pre class=codeResult>house has:
4 occupants
2500 total area
Display the area per person.
625 area per person
office has:
25 occupants
4200 total area
Display the area per person.
168 area per person</pre>

==Call base constructor to init member variables==

<source lang="csharp">public class A
{
public A( int x )
{
this.x = x;
}
public A() : this( 0 )
{
}
internal int x;
}
public class B : A
{
public B() : base( 1 )
{
}
}
public class MainClass
{
static void Main()
{
B b = new B();
System.Console.WriteLine( "A.x = {0}", b.x );
}
}</source>
<pre class=codeResult>A.x = 1</pre>

==field initialization==

<source lang="csharp">class FieldInitExample
{
int x = 5;
int y;
public FieldInitExample() : this(5)
{
}
public FieldInitExample(int y)
{
this.y = y;
}
}</source>

==fields==

<source lang="csharp">class FieldExample
{
private static int idCounter;
protected int id;
public string name;
public int x;
public int y;
private System.DateTime createDate;
}</source>

==How to use a "has a" relationship==

<source lang="csharp">public class Engine
{
public int cylinders;
public int horsepower;
public void Start()
{
System.Console.WriteLine("Engine started");
}
}
public class Car
{
public string make;
public Engine engine; // Car has an Engine
public void Start()
{
engine.Start();
}
}
class MainClass
{
public static void Main()
{
System.Console.WriteLine("Creating a Car object");
Car myCar = new Car();
myCar.make = "Toyota";
System.Console.WriteLine("Creating an Engine object");
myCar.engine = new Engine();
myCar.engine.cylinders = 4;
myCar.engine.horsepower = 180;
System.Console.WriteLine("myCar.make = " + myCar.make);
System.Console.WriteLine("myCar.engine.cylinders = " + myCar.engine.cylinders);
System.Console.WriteLine("myCar.engine.horsepower = " + myCar.engine.horsepower);
myCar.Start();
}
}</source>
<pre class=codeResult>Creating a Car object
Creating an Engine object
myCar.make = Toyota
myCar.engine.cylinders = 4
myCar.engine.horsepower = 180
Engine started</pre>

==Illustrates how to assign default values to fields using initializers==

<source lang="csharp">class PC
{
public string make = "AAA";
public string model = "T";
public string color;
public int yearBuilt = 1910;
public void Start()
{
System.Console.WriteLine(yearBuilt + " yearBuilt");
}
}
class MainClass
{
public static void Main()
{
PC myPC = new PC();
System.Console.WriteLine("myPC.make = " + myPC.make);
System.Console.WriteLine("myPC.model = " + myPC.model);
if (myPC.color == null)
{
System.Console.WriteLine("myPC.color is null");
}
System.Console.WriteLine("myPC.yearBuilt = " + myPC.yearBuilt);
}
}</source>
<pre class=codeResult>myPC.make = AAA
myPC.model = T
myPC.color is null
myPC.yearBuilt = 1910</pre>

==Use this and base together to init a class==

<source lang="csharp">using System;
class Base
{
public Base( int x )
{
Console.WriteLine( "Base.Base(int)" );
this.x = x;
}

public int x = 0;
}
class Derived : Base
{
public Derived( int a ):base( a )
{
Console.WriteLine( "Derived.Derived(int)" );
this.a = a;
}
public Derived( int a, int b ):this( a )
{
Console.WriteLine( "Derived.Derived(int, int)" );
this.a = a;
this.b = b;
}
public int a = 0;
public int b = 0;
}
public class MainClass
{
static void Main()
{
Derived b = new Derived( 1, 2 );
}
}</source>
<pre class=codeResult>Base.Base(int)
Derived.Derived(int)
Derived.Derived(int, int)</pre>

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Csharp/CSharp Tutorial/Class/Member Variable - История изменений

в 15:31, 26 мая 2010

Admin: 1 версия