A Closer Look at C# Classes - Part 1

C# has both a constructor and a destructor, which looks and behaves similarly to C++. A class constructor is called when an object is instantiated and the destructor is called when the object is destroyed. Expanding our previous listing, we'll add a constructor and destructor.

Listing 2
abstract class Mammal {
void Walk() {
} }

sealed class Human : Mammal {
string m_name;

// -- constructors
public Human() {
}

public Human(string Name) {
m_name = Name;
}

// -- destructors
~Human() {
}

void Walk( ) {
System.Console.WriteLine("{0} walks on two legs.\n",m_name);
}
}

class Example {
static void Main() {
class Human Athlete = new Human("Jeff");
Athlete.Walk();
}
}

In C#, having the same name as the class signifies a constructor. You will notice that in Listing 2, there are two constructors for the Human class. C# distinguishes the two constructors by their signature. If you look closer, one of the constructors require a parameter where the other doesn't. When we instantiated an object and passed "Jeff" as the parameter, C# recognizes that the second constructor is requested.

In this article, we've dealt with four concepts dealing with classes in C# - abstract, sealed, constructors and destructors. Strings in C# is a lot easier to manage and almost eliminates common mistakes made in C/C++. I've given an insight as to how strings are managed in C# in Listing 2.

Copyright © 2001 Jose Aniceto

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