C++ (Logical Copy Constructor) How do I copy an object?

Question

I have a class:

class Person{
public:
    Person();
    ~Person();
    string name;
    int* age;
};

int main()
{
    Person* personOne = new Person;
    personOne->name = "Foo";
    personOne->age = new int(10);


    return 0;
}

How do I create another object of Person that copies all of personOne data? The age pointer needs to be pointing to a new int so whenever the age changes in personOne or personTwo, it doesn't affect each other.

Answer 1

There are two posibilites:

• copy constructor + assignment operator
• clone method

Code:

class Person{
public:
    Person();
    ~Person();
    Person (const Person& other) : name(other.name), age(new int(*(other.age)))
    {
    }
    Person& operator = (const Person& other)
    {
        name = other.name;
        delete age; //in case it was already allocated
        age = new int(*(other.age))
        return *this;
    }
    //alternatively 
    Person clone()
    {
        Person p;
        p.name = name;
        p.age = new int(age);
        return p;
    }

    string name;
    int* age;
};

Answer these before going forward:

• do you really need an int pointer?
• are you aware of smart pointers?
• do you free all memory you allocate?
• do you initialize all members in the constructor?