Assigning an array of pointers to a private variable in C++

Question

In my header file, I have the following code

class ExEvent : public Event {
    public:
        ExEvent(
                Item* dst[SIZE],
                );
        ~ExEvent();
        Item* dst[SIZE];
};

In the cpp file, I have the following code

ExEvent::ExEvent(
        Item * dst[SIZE],
    ) : Event() {
    this->dst = &dst;
}

I get the following error:

error: array type 'Item *[15]' is not assignable
    this->dst = &dst;

Can someone explain why this error happens and why I cannot assign dst array pointer to this->dst.

You cannot directly assign arrays. Use std::copy instead, or even better use std::array in 1st place. — πάντα ῥεῖ
– πάντα ῥεῖ, Commented Nov 22, 2016 at 15:12
You have to copy the pointers to the array. You can't assign multiple pointers to a pointer array with '='. Use std::copy or memcpy. — Scott Mudge
– Scott Mudge, Commented Nov 22, 2016 at 15:19
You can eliminate the this-> syntax by giving your parameters different names than your member variables. — Thomas Matthews
– Thomas Matthews, Commented Nov 22, 2016 at 15:32

Maxim Egorushkin · Accepted Answer · 2016-11-22 15:23:33Z

4

In function arguments type[any-size] is actually type*. I.e. ExEvent(Item*[SIZE]) is, in fact, ExEvent(Item**).

Hence, to fix the code:

ExEvent::ExEvent(Item* src[SIZE])
{
    std::copy_n(src, SIZE, this->dst);
}

Make sure that src has enough elements.

See declaring functions: parameter list for more details:

If the type is "array of T" or "array of unknown bound of T", it is replaced by the type "pointer to T"

edited Nov 22, 2016 at 15:23

answered Nov 22, 2016 at 15:17

Maxim Egorushkin

138k19 gold badges201 silver badges293 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Assigning an array of pointers to a private variable in C++

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related