Question

class WavFile
{
    std::vector<short> SoundData;

public:

    std::vector<short> getSoundData()
    {
        return SoundData;
    }
}

Normally I’d use fread( &SoundData[0], 1, 1337, SomeFile );

But now that I’m using a vector inside a class, I’m having trouble with the following:

• Knowing how to set the vector size outside the class.

• And I’m not sure how to use the method as an argument for fread to put the data inside the vector.

Answer 1

What you are trying to do is bad in general. There are some main points to it:

If you are encapsulating vector in class, you can still operate on it normally from the outside if it’s public.

WavFile WF;
void* Ptr = WF.SoundData.data();
// void* Ptr = &WF.SoundData[0]; - C++03

You can also wrap some of the calls to the vector, .resize() for example:

void WavFile::resize(vector::size_type new_size) {
    SoundData.resize(new_size);
}

void* WavFile::getRawPtr () {
    return SoundData.data();
    // return (&SoundData[0]); - C++03
}

If you are using std::vector, you should also use corresponding C++ read functions on it. Treating vector as a memory array is valid, but there are better ways to use it, fstream for example.

If you are encapsulating vector (or any std container in general), don’t return it by value! It will cause all of the elements to be copied. Instead, return a const-reference to container, or, even better, range.