Any language welcome challenge

wtd · **Posted:** Tue Feb 05, 2008 11:38 pm

Well, any language in which one can write a program that satisfies the problem description. Wink

Create a generic class Foo which takes as its type parameter T any class which answers to a method "baz" which returns an integer. The generic class Foo must have a constructor which takes an object of type T, storing that as "x". Foo must have a method qux which returns the result of multiplying x's baz method's return value by three.

rdrake · **Posted:** Tue Feb 05, 2008 11:40 pm

Are we to post our solutions here?

wtd · **Posted:** Wed Feb 06, 2008 12:28 am

Yes.

To kick it off:

code:

class ['t] foo (x : 't) =
object
method qux = x#baz * 3
end

rdrake · **Posted:** Wed Feb 06, 2008 1:20 am

Good old C# 2.0:

code:

public interface IWooble
{
int Wooble();
}

public class WoobleObject : IWooble
{
public int Wooble()
{
return 42;
}
}

public class Baz<T> where T:IWooble
{
private T _O;

public Baz(T o)
{
this._O = o;
}

public int Ninja()
{
return this._O.Wooble() * 3;
}
}

public class Test
{
public static void Main(string[] args)
{
Baz<IWooble> b = new Baz<IWooble>(new WoobleObject());
System.Console.WriteLine(b.Ninja());
}
}

OneOffDriveByPoster · **Posted:** Wed Feb 06, 2008 11:11 am

code:

template <typename T>
class Foo {

T x;

public:
Foo (T const &x) : x(x) { }
int qux(void) {
return x.baz() * 3;
}
};

Hopefully close enough...

wtd · **Posted:** Wed Feb 06, 2008 5:43 pm

Excellent.

rdrake · **Posted:** Fri Feb 08, 2008 3:46 am

Improved C# 3.0 version:

code:

public class WoobleObject
{
public virtual int Wooble() { return 42; }
}

public class Baz<T> where T : WoobleObject
{
public T O { get; set; }

public int Ninja() { return this.O.Wooble() * 3; }
}

public class Test
{
public static void Main(string[] args)
{
var b = new Baz<WoobleObject>() { O = new WoobleObject() };
System.Console.WriteLine(b.Ninja());
}
}

EDIT: Dan, why does uppercase Test get changed to just lowercase test?

wtd · **Posted:** Fri Feb 08, 2008 1:34 pm

Scala:

code:

trait Baz {
def baz: Int
}

class Foo[T <: Baz](val x: T) {
def qux = x.baz * 3
}

object Test extends Application {
val f = new Foo(new Baz { def baz = 42 })
Console println (f qux)
}

rdrake · **Posted:** Sat Feb 09, 2008 1:24 am

Another:

Ruby:

class WoobleObject
def wooble
42
end
end

class Baz
def initialize(o)
@o = o
end

def ninja
@o.wooble * 3
end
end

puts Baz.new(WoobleObject.new).ninja

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