C++ copy constructor with object pointer as argument

Question

I'm still a bit shaky about C++'s copy and assignment constructors. So far what I have is in A.hpp:

class A {
private:
     char* str;
public:
     A(char* str);

     // strcpy str from other to this.
     A(const A& other);

     // free str in this, and strcpy str from other to this.
     A& operator=(const Type& other);
}

Assuming I have A* a = new A(some_char_str); , I'm able to write A b = *a;, and b is a deep copy of a. Now the problem is that I want the ability to write A* b = new A(a); So how can I specify a constructor that takes a pointer to A and create a new A on the heap?

Why not try it first? If there is an error, let us know. No need to suffer from "analysis paralysis". — PaulMcKenzie
– PaulMcKenzie, Commented Mar 27, 2015 at 17:45
@PaulMcKenzie Well... I just felt like I'm an idiot... I'm think about the copy/assignment constructor thing too hard... — fleetC0m
– fleetC0m, Commented Mar 27, 2015 at 17:48
@fleetC0m don't be hard on yourself. At least you gave it some thought, which is more than a lot of people do. — WhozCraig
– WhozCraig, Commented Mar 27, 2015 at 17:53

fleetC0m · Accepted Answer · 2015-03-28 21:49:02Z

1

Oh well the brain fart... I just realized I can provide a constructor A::A(const A* other) myself without using copy/assignment constructor, or just write A* b = new A(*a); as suggested in comment.

edited Mar 28, 2015 at 21:49

answered Mar 27, 2015 at 17:48

fleetC0m

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3 Comments

PaulMcKenzie Over a year ago

I think your original code had all of the necessary parts to perform what you requested. That's why I ask that you try it first.

PaulMcKenzie Over a year ago

BTW, If a is a pointer to an A, you had all the pieces already done in your original code: A* newA = new A(*a); This will call your copy constructor (which you coded) -- no need for another constructor that takes a pointer to A

fleetC0m Over a year ago

@PaulMcKenzie When I try A* b = new A(*a);, I got error: no viable conversion from 'A *' to 'A'. That is without the A(const A* other); constructor of course

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