// This is an improved version of combo3 that minimizes copying.  We tell the
// vector to make room for 4 values after we construct it and we pass the
// vector as a const reference parameter with the foreach loop also using a
// const reference for each item.  We use the emplace_back function of the
// vector class where we provide the parameters to use for constructing a combo
// object.  Then the vector does the constructing, which elminates the need for
// copying.

#include <iostream>
#include <string>
#include <vector>

using namespace std;

class combo {
public:
    combo(int initial_value = 0, const string & initial_text = "foo") {
        value = initial_value;
        text = new string(initial_text);
        cout << "in regular constructor" << endl;
    }

    // copy constructor
    combo(const combo & rhs) {
        value = rhs.value;
        // default is shallow copy: text = rhs.text
        text = new string(*rhs.text);
        cout << "in copy constructor" << endl;
    }

    // assigment operator
    combo & operator=(const combo & rhs) {
        if (this != &rhs) {
            value = rhs.value;
            // default is shallow copy: text = rhs.text
            *text = *rhs.text;
        }
        cout << "in assignment operator" << endl;
        return *this;
    }

    // destructor
    ~combo() {
        delete text;
        cout << "in destructor with value = " << value << endl;
    }

    int get_value() const {
        return value;
    }

    const string & get_text() const {
        return *text;
    }

private:
    int value;
    string * text;
};

void print(const vector<combo> & v) {
    cout << "entering foreach loop" << endl;
    for (const combo & c : v) {
        cout << c.get_value() << " " << c.get_text() << endl;
    }
}

int main() {
    combo c(42, "hello");
    cout << endl;

    vector<combo> v;
    v.reserve(4);
    v.emplace_back(3, "bar");
    v.emplace_back(15, "baz");
    v.emplace_back(7, "mumble");
    v.emplace_back(c.get_value(), c.get_text());
    
    cout << "calling print:" << endl;
    print(v);

    return 0;
}