CODEWITHSUNDEEP
c++oop
tariq zafar
tariq zafar

Reputation: 659

Query related to constructors in inheritance

I have a question related to inherotance.

I declare a class and then declare a child class as below

`Producer::Producer(Pool<string>* p, string id) {
    mPool = p;  // protected members
    mId = id;
}

ProduceCond::ProduceCond(Pool<string>* p, string id) {
    Producer(p, id);
}

class Producer{
}

class ProduceCond : public Producer, public ThreadSubject {
}

`

Though I have called right parent constructor in the child constructor I receive an error

ProduceCond.cpp:10:52: error: no matching function for call to ‘Producer::Producer()’

Can someone tell me why I receive this error although I use correct constructor format of the parent?

Upvotes: 0

Views: 52

Answers (2)

billz
billz

Reputation: 45410

To initialize sub-object(base) which has no default constructor, you need to call it through member initializer list:

ProduceCond::ProduceCond(Pool<string>* p, string id) : Producer(p, id) {}

Or you could provide a default constructor which will be called implicitly by sub-class constructor

Producer() : mPool(std::nullptr) { }

Also you have to use member initializer in below conditions:

1 You must (at least, in pre-C++11) use this form to initialize a nonstatic const data
member.

2 You must use this form to initialize a reference data member.

Upvotes: 1

juanchopanza
juanchopanza

Reputation: 227390

You need to use the constructor initialization list:

ProduceCond::ProduceCond(Pool<string>* p, string id)  : Producer(p, id)
{
  ....
}

Otherwise, you are default constructing a Producer (which you can't, because it has no default constructor), then doing something strange in the body of the constructor.

Upvotes: 2

Related Questions