Class lookup structure array in C++

Question

I\'m trying to create a structure array which links input strings to classes as follows:

struct {string command; CommandPath cPath;} cPathLookup[] = {
    {\         


        

Answer 1

You can't store a type in a struct, but you can store a pointer to a function that creates a type.

CommandPath * CreateEmail() {
     return new EmailCommandPath;
}

CommandPath * CreateAlarm() {
     return new AlarmCommandPath;
}

Then your struct looks like:

typedef Command * (* CreateFunc)();
struct MyMap {
   string command;
   CreateFunc func;
};

and the map:

MyMap m[] = {{"email", CreateEmail }, {"alarm", CreateAlarm}};

You then look up as before to get some index i, and use it:

CommandPath * p = m[i].func():

And you can create pointers to abstract types - you can't create instances of them.