How to get the number of elements in a struct?

Question

I declared a struct for some options that shall be filled by command line arguments or by reading an input file:

struct options {
  int val1;
  int val2;
  bool val3;
}

Now I want to check for the correct number of arguments at execution of the program. Sure thing a

const int optionsSize = 3;

would do. But is there any adaptive way? What if I add another value into the struct and don't remember to increase the integer?

Answer 1

Why not add the options as specified into an std::vector<string> options and use the options.size() method to check the correct number. Then convert them to the proper datatype.

A more robust way of doing this kind of thing would be to use Boost Program Options