CODEWITHSUNDEEP
c++inheritanceconstructorinitialization-list
xaviersjs
xaviersjs

Reputation: 1737

C++ initialization list in second derrived class

I'm trying to write a relatively deep class heirarchy and my compiler keeps throwing "no matching function for call to [default constructor for bass class]". Here's the scenario:

Class A {
    A(int);//note, no default constructor
}

Class B : public A {
    B(int i, int j) : A(i), someMemberVariable(j) {}
    int someMemberVariable;
}

Class C : public B {
    C(int k, int l) : B(k, l) {}
}

and the compiler throws the error on the line for the constructor of class C saying "no matching function for call to A::A()" and tells me to use A::A(int).

I understand that I don't have a default constructor for class A, and the compiler is getting confused when I try to subclass a subclass. However, what I don't understand is why. I have used an initialization list to avoid exactly that. If I only use classes 2-levels deep then it works just fine, but the third class gives me the error. What am I doing wrong here?

Upvotes: 0

Views: 426

Answers (1)

Connor Hollis
Connor Hollis

Reputation: 1155

As people commented you just needed to make the constructors public and then your code had some formatting issues:

class A 
{
  public:
    A(int a) : blah(a) {}; //note, no default constructor
    int blah;
};

class B : public A 
{
  public:
    B(int i, int j) : A(i), someMemberVariable(j) {}
    int someMemberVariable;
};

class C : public B 
{
  public:
    C(int k, int l) : B(k, l) {}
};

int main( void )
{
  C c(5,4);
  return 0;
}

This code compiles cleanly and does what you want.

Upvotes: 3

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