Re: Converting new [] to vectors

From:
"Andrew Wall" <wallguide-usenet1@yahoo.com>
Newsgroups:
comp.lang.c++.moderated
Date:
Sat, 27 Feb 2010 13:17:00 CST
Message-ID:
<ENdin.137029$jI5.12183@newsfe08.ams2>
"Daniel T." <daniel_t@earthlink.net> wrote in message
news:61261907-55cc-41d9-945b-322c020e6a7e@e23g2000yqd.googlegroups.com...

On Feb 26, 5:31 pm, Richard Howard <rhphotography....@googlemail.com>
wrote:

I am currently working on some legacy software, and I tend to replace
calls to new/delete with auto_ptrs and new[]/delete[] with vectors ...
but how do I implement the following whist maintaining RAII, is there
a std method of doing this?

    float (* coords)[3] = NULL;
...
    long numPoints = sourceOfPoints->size();
    coords = new float[numPoints][3]; // allocate the array of arrays
    sourceOfPoints->GetPointAll(coords); // set the appropriate array
values on the array of arrays
...
    delete [] coords;

I thought maybe

    vector<float[3]>

but it complains at me


I would be inclined to do something like this:

struct Point3D
{
    float value[3];
    float operator[](int i) const { return value[i]; }
    float& operator[](int i) { return value[i]; }
};

vector<Point3D> coords;
coords.resize(sourceOfPoints->size());
sourceOfPoints->GetPointAll(coords);


I can heartily recommend this method: Wrap primitives, like pointers and
arrays, within a struct or class. It always simplifies the syntax needed to
access to the underlying data.

Andrew Wall

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