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
