Question

I want to create an array of structures. The structure uses a constructor as shown below:

struct struct_seedinfo {
    struct_seedinfo(const mxArray *prhs[ ],const int seed_id){  
        mxArray *mat_coords, *mat_defvectorinit, *mat_corrcoef, *mat_roi_id;

        mat_coords = mxGetField(prhs[1],seed_id,"coords");
        coords = mxGetPr(mat_coords);

        mat_defvectorinit = mxGetField(prhs[1],seed_id,"defvectorinit");
        defvectorinit = mxGetPr(mat_defvectorinit);

        mat_corrcoef = mxGetField(prhs[1],seed_id,"corrcoef");
        corrcoef = *(mxGetPr(mat_corrcoef));

        mat_roi_id = mxGetField(prhs[1],seed_id,"roi_id");
        roi_id = *(mxGetPr(mat_roi_id));
    }
    double *coords;
    double *defvectorinit;
    double corrcoef;
    double roi_id;
    static int num_seeds;
};

How could I create an arbitrary sized array of this structure? I need to allocate memory for it, but it seems like I would need to allocate memory without calling the constructor, and then call the constructor later in a forloop. Is there a good or preferred way of doing this? Thanks.

Answer 1

You can do std::vector<struct_seedinfo>. This will create an array and it will automagically increase in size when needed.

You’ll also need to overload the copy constructor and copy-assignment operator for your struct to be able to be used in a vector. You need a destructor too. This is called the Rule of Three in C++