How to compile and use an external class

[Derek Parnell]

On Tue, 2 Dec 2008 09:28:53 +0000 (UTC), Some Guy wrote:

> I am busy learning D and I want to be able to use classes now. I am
> used to programming in C# where it does everything for you and you
> don't have to think about this kind of thing so I now have no idea
> how to compile a program from the command line that uses a class in
> another source file.
> 
> I have a source file called MyProgram.d which contains the main
> program and I have a file called MyClass.d that contains a class
> called MyClass. I want to be able to create an instance of MyClass in
> the main program but I don't know what to type to compile it the
> command line. This is what I have tried so far which doesn't work:
> 
> dmd MyProgram.d MyClass.d
> 
> Thanks in advance for your help.

Seeing that you didn't show us your code, I took the liberty of writing
some example code...

---------- myprogram.d ---------
module myprogram;

// Tell the compiler that this file needs to know
// about what is in the file 'myclass.d'
import myclass;

import std.stdio;    // Need this to use writefln();

void main()
{
    // Create an instance of the class.
    MyClass inst = new MyClass();
    
    // Invoke a method in the instance.    
    writefln("First %s", inst.A_Method());
    
    
    // Create another instance of the class.
    MyClass yai = new MyClass(5);
    
    // Invoke a method in the instance.    
    writefln("Second %s", yai.A_Method());
}
--------- end of file -------------


---------- myclass.d ---------
module myclass;
class MyClass
{
    int SomeAttribute;
    // A class constructor 
    this()
    {
        SomeAttribute = 1;
    }
    
    // Another class constructor 
    this(int InitData)
    {
        SomeAttribute = InitData;
    }
    
    
    // A method
    int A_Method()
    {
        return SomeAttribute;
    }
    
}
--------- end of file -------------


The line to compile these ...

   dmd myprogram myclass

When running the program 'myprogram' you should get ...

c:\>myprogram
First 1
Second 5

-- 
Derek Parnell
Melbourne, Australia
skype: derek.j.parnell