Class constructor
In this chapter you will learn:
Add constructor to a class
A constructor initializes an object when it is created. A constructor has the same name as its class. A constructor is syntactically similar to a method. Constructors have no explicit return type.
The general form of constructor is shown here:
access class-name( ) {
// constructor code
}
Constructors can have the following modifiers:
- public
- internal
- private
- protected
- unsafe
- extern
You can use a constructor to give initial values to the instance variables.
using System; //j a v a2s . c o m
class MyClass {
public int x;
public MyClass() {
x = 10;
}
}
class ConsDemo {
public static void Main() {
MyClass t1 = new MyClass();
MyClass t2 = new MyClass();
Console.WriteLine(t1.x + " " + t2.x);
}
}
The code above generates the following result.
A parameterized constructor
Constructors can have parameters. The following code uses the contructor to initialize the fields.
using System;/*from j a v a 2 s. c om*/
class Rectangle{
public int Width;
public int Height;
public Rectangle(int w, int h){
Width = w;
Height = h;
}
}
class Program
{
static void Main(string[] args)
{
Rectangle r = new Rectangle(1, 2);
Console.WriteLine(r.Width);
}
}
The output:
using System; // ja v a 2 s . c om
class MyClass {
public int x;
public MyClass(int i) {
x = i;
}
}
class MainClass {
public static void Main() {
MyClass t1 = new MyClass(10);
MyClass t2 = new MyClass(88);
Console.WriteLine(t1.x + " " + t2.x);
}
}
The code above generates the following result.
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What you will learn in the next chapter:
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