Accessing Structure Members Problems

Question

I am new to C++ classes and facing a simple problem but unfortunately didn't get the solution yet so that's why posting it here. I made a struct like this

struct mono_scan_temp
{
    double num_filters[1][1];
    double filter_data[1024][153][3];
    double shutter_speed[1][3];
    double resolution[1][153];
    double monochromator_gain[1][1];
    double zero[1][1];
    double saturation[1][1];
    double dark_noise[3][1024];
    double slit_size[1][1];
    double version[1][1];
};

This struct is in .h file then i instantiated it in the same header file like this

mono_scan_temp          scan_data_temp;

Now when i am trying to access its members from a main file it is giving this error.

Error 43 error C2228: left of '.num_filters' must have class/struct/union

The members of this struct will hold a data from .mat file like this

Mat_VarReadData(mat,field_num_filters,scan_data_temp.num_filters,start_num_filters,stride_num_filters,edge_num_filters);

for(i=0;i<field_num_filters->dims[0];i++)
for(j=0;j<field_num_filters->dims[1];j++)
printf("%f \n  ",scan_data_temp.num_filters[i][j]);

and also the header file is included in the main file.

I know it a simple problem but sorry in advance for my limited knowledge.

Looking forward for a favorable response.

Thanks

Answer 1

You apparently have a subexpression XXX.num_filters , and XXX isn't an object of type mono_scan_temp .

Defining zero to be a two-dimensional array of bound 1 in each dimension, and a member of a struct , is what those in the industry sometimes call a "code smell."

---

This line does not go in the header file; it should go in the .cpp file. To declare a global object as part of an interface in the header, add extern before the declaration: extern mono_scan_temp scan_data_temp; . This is in addition to defining in the .cpp file.

And although the rest of your program appears to be in C, this line does require C++, so be sure you are using a C++ compiler and the file name ends in .cpp (if that's really what you want).

mono_scan_temp          scan_data_temp;