Vector contents into array (only first element gets copied)

[nicolee]

Hi,

I have a function that takes in vectors as parameters and then converts them into array and then calls a third party library function. I searched that to copy the contents of the vector into an array, this is one way:

double* data = new double[svr.voice.size()];//voice is the vector which is a global variable in a class SVR
copy(svr.voice.begin(), svr.voice.end(), data);

However, only the first element is being copied. I repeatedly call this function inside a while loop and every time the vector size increases by 1, but the array just always contains the first index.

Any ideas why? Any help would be greatly appreciated! Thanks!

[Galik]

If you don't want to make a copy of the elements you don't have to. You can take the address of the first element in the vector and pass this to the function expecting an array:

Something a bit like this:

void process_array(double* array, size_t size)
{
    for(size_t i = 0; i < size; ++i)
    {
        // ... do stuff to array[i];
    }
}

int main()
{
    std::vector<double> v;

    v.push_back(3.14);
    v.push_back(6.2);
    v.push_back(0.9);

    process_array(&v[0], v.size());
}

[vlad from moscow]

Check whether svr.voice.size() is equal to 1.

[coder777]

Well: copy(svr.voiceArousal.begin(), svr.voice.end(), data);

[nicolee]

Hi all,

Thanks for your replies. Apparently, my code already works. I just thought that my array has only one value that's why the library function is not working. Sorry for the trouble.


Thanks!