Question

I am following the Preamble: what is a reference type? where it explains parameters passing as value or reference type. The first example has the following code:

using System;
using System.Text;

public class Example1
{
    public static void Main (string[] args)
    {
        StringBuilder first = new StringBuilder();
        StringBuilder second = first;
        first.Append ("hello");
        first = null;
        Console.WriteLine (second);
    }
}

And it does not provide the source code for the class (or struct) of StringBuilder, and I do not know how the Console.WriteLine(second) is able to return a string value just by using the identifier. Is it possible to return a value in the constructor?

I tried to write the class or struct by following (and it doesn’t work):

struct StringBuilder
{
    private string _myString;
    public string StringBuilder
    {
        get { return _myString; }
        set { _myString = value; }
    }
    public void Append(string str)
    {
        _myString = str;
    }
}

Answer 1

Have a look a the documentation for Console.WriteLine(object value). It says this:

the ToString method of value is called to produce its string
representation, and the resulting string is written to the standard
output stream.

So (as others have written), if you want to print a string representation of your own class or struct, you should override the ToString() method.