Class instantiation function

Question

Hello am trying to learn C#, I came across this code from a C# tutorial:

Public Class A()
{
    Public A () : this(capacity:10) 
    {
    }

    public int capacity 
    {
        get { return _buffer.length;}
    }
}

I just did not understand why he used : between Public A () and this(capacity:10).

I did not know what to search for on Google so I decided to ask here.

My question is: what is this used for and why?

Personally, I would try harder figuring it out, before asking on Stack Overflow. — Uwe Keim, Feb 13 '17 at 14:00

score 0 · Accepted Answer · answered Feb 13 '17 at 14:05

The code provided doesn't compile. Probably, the code be something like this:

  // lower case for "public" and "class" 
  public class A {
    // _buffer is addressed in "capacity" property, let it be an array 
    private int[] _buffer = new int[10];

    // this constructor is mandatory for the code below
    public A(int capacity) {
    }

    // Now, your question:
    // "this(capacity: 10)" calls the costructor above 
    // "public A(int capacity)"
    // while passing the "capacity" parameter by its name
    public A () : this(capacity: 10)
    {
    }

    public int capacity {
    get {
      return _buffer.Length;
    }
  }

If I guessed right this(capacity: 10) is a call of the constructor public A(int capacity) while passing capacity by name

Class instantiation function

1 Answers1