Question

have written this little class, which generates a UUID every time an object of this class is created.

#include <boost/uuid/uuid.hpp>
#include <boost/uuid/uuid_generators.hpp>
#include <boost/uuid/uuid_io.hpp>    

class myClass {

public:

    boost::uuids::uuid GetUUID();

    virtual ~myClass();

    myClass() {   // constructor
        mId = boost::uuids::random_generator()();
        std::cout<< "object created with uuid " << mId <<std::endl;
    }

private:

    boost::uuids::uuid mId;

}

At some point, I am pushing these objects to a vector and equating that vector with another vector using simple assignment operator. To ensure the objects in the new vector do not generate new UUIDs, I want to write a copy constructor. But as you can see, the constructor needs no arguments. So I am not sure how to write the copy constructor. Moreover, if I have multiple variables instead of just one UUID, how do I handle that situation?

Answer 1

You need the following signature:

 myClass(const myClass& other)
 {
     mId = other.mId;
 }

and also the assignment operator

 myClass& operator=(const myClass& other)
 {
     mId = other.mId;
     return *this;
 }

Note that if you don’t implement these, the compiler-generated ones will do a shallow copy, so no new UUIDs will be generated. But you should have them there to obey the rule of three (you do have a destructor after all).