Const and reference members

consttest.cpp

#include <iostream>
#include <string>

using namespace std;

class MyThing
{
public:
    /*
     * Have to override default constructor to initialize const and reference members.
     * Note mVarValue doesn't have to be explicitly initialized. Args almost
     * always have to be passed to initialize these members.
     */
    explicit
    MyThing(const string& refValue) : mConstValue(0), mRefValue(refValue) {}

    /* Default copy constructor is usually OK.
    MyThing(const MyThing& other) :
        mConstValue(other.mConstValue),
        mRefValue(other.mRefValue),
        mVarValue(other.mVarValue) {}
    // */

    /*
     * Have to override default assignment operator and ignore these members.
     */
    //*
    MyThing& operator=(const MyThing& other)
    {
        mVarValue = other.mVarValue;
        // can't assign const/ref once initialized
        return *this;
    }
    // */

private:
    const int mConstValue;
    const string& mRefValue;
    string mVarValue;
};

int
main(int arc, char** argv)
{
    // If anything ever actually uses mRefValue, this memory has to still
    // be around (up to the caller).
    string name("thing");

    // constructor
    MyThing thing(name);

    // copy constructor
    MyThing otherThing(thing);

    // assignment operator
    otherThing = thing;

    return 0;
}