Thread: Need help (migrating from java)

I would do:

Code:

class Test
{
    private:
         int a, b;

    public:
         Test( int a, int b ){ this->a = a, this->b = b; }
         virtual void print=0; //make abstract
}

class TestChild :: public Test
{
    private:
         int a, b, c
 
    public:
          TestChild( int a, int b, int c ) : Test(a, b)
         { 
                     this->c = c;
           }
          
          void print(){ cout << "I am printing..."; }
}

Also, I prefer to use different names for the arguments to the constructor and the class members.

E.g:

Code:

          TestChild( int aa, int ab, int ac ) : Test(aa, ab)
         { 
                     c = ac;
           }

That way, you don't need to use "this->" all over the place.

Neither of my suggestions will affect what happens.

--
Mats

Originally Posted by John_L

Code:

class TestChild : public Test
{
    private:
         int a, b, c
 
    public:
          TestChild( int a, int b, int c ) : Test( a, b ) 
          {
                     this->c = c;
          }
          
          void print(){ cout << "I am printing..."; }
}

In C++ there is no "super" keyword, you need to know the base class' name ( probably because you can have more than one base class, so "super" would be ambigous ).

Originally Posted by John_L

ok thanks. Couple more questions:

1) Matsp: Does it make a difference if you include it in the method header versus the method
body (as i did)?

It makes no functional difference - it's just "style".

2) When does using "friends" become necessary?

When a class or function needs to access private data of another class that it's not a member of.
E.g.:

Code:

class X
{
private:
   int x;
...
   friend void print(X a);
...
}

void print(X a)
{
   cout << a.x << endl;
}

3) What about when you start having multiple subclasses, which extend a subclass of the base class? Do you travel up the hierarchy the same way, or can the Test 3 actually envoke base Class Test methods itself?

ex)

Code:

class Test

class Test2 : public Test

class Test 3 : public Test2

[/QUOTE]

Normally, Test3 calls Test2's constructor, Test2 then calls Test constructor. Either implicitly or explicitly. But there should be no need for Test3 to call Test explictly - you shouldn't need to know about Test inside Test3.

--
Mats