I have inherited some code that I am looking at extending, but I have come across a class\constructor that I have not seen before. Shown below in the code snippet
class A { public: A() {}; ~A() {}; //protected: int value_; class B: public std::vector<A> { public: B(int size = 0) : std::vector<A>(size) {} So from what I gather class B is a vector of class A which can be accessed using the *this syntax because there is no variable name. I would like to initiate class A in the constructor, but I am unsure how to do this with in this context. I have looked at this but they have declared the vector as an object where in this case it is the class.
This seems slightly different from normal inheritance where I have inherited many instances of a single class, compared to the usual one to one in most text books. What I was trying to do, was propagate a value to intialise class A through both class B and class A constructor. Something like below is what I tried but doesn't compile.
#include <iostream> #include <vector> using namespace std; class A { public: A(int int_value) : value_(int_value) {}; ~A() {}; //protected: int value_; }; class B: public vector<A> { public: B(int size = 0, int a_value) : vector<A>(size, A(a_value)) {}; vector<int> new_value_; void do_something() { for (auto& element : *this) new_value_.push_back(element.value_); } }; int main() { cout << fixed; cout << "!!!Begin!!!" << endl; B b(20,23); cout << b.size() << endl; b.do_something(); for(auto& element : b.new_value_) cout << element << endl; cout << "finished" << endl; system("PAUSE"); return 0; } I guess a follow up question is, is this a good implementation of what this code is trying to achieve
