Using base default constructor (with parameters) for child class

Question

I have a class A which has to have a a class passed to it; From A I have two classes B and C; is it possible for B and C to use the constructor from A, as apposed to the default constructor.

     A
    / \
   B   C 

A::A(randomNumber &rnd)
{
    ....
}

ForEveR · Accepted Answer · 2013-03-22 11:18:34Z

3

Yes. Use

class B {
public:
   B() : A(someRndNum) {}
};

and same for C.

answered Mar 22, 2013 at 11:18

ForEveR

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Comments

Andy Prowl · Accepted Answer · 2013-03-22 11:19:00Z

0

Yes, it is possible:

class B
{
public:
    B(randomNumber& rnd) : A(rnd) { }
    // ...
};

If you want to call A's constructor in B's default constructor, you will have to pass a global object: since A's construct accepts an lvalue reference, creating a temporary is not an option.

B() : A(global_random_number);

answered Mar 22, 2013 at 11:19

Andy Prowl

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1 Comment

KingJohnno Over a year ago

Brilliant - thank you. For anyone looking at this answer You should not include type names in function calls... it confuses the compiler. Something I had to work out :-)

Azodious · Accepted Answer · 2013-03-22 11:20:48Z

0

You can use following syntax:

B::B() : A(aRandomNum)
{
    ....
}

answered Mar 22, 2013 at 11:20

Azodious

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