Question

Is it possible to set a member attribute in a “generic” way?
I am still new to c++ and just dived into templates, if this is the way to go?

The class i have to use has around 20 string members to be filled from informix database and i could loop through an array with the field(=attribute) names.

Let’s say i have a simple class

class Foo
{
  public:
    attr1
    attr2
  Foo() { };
  ~Foo();
}

and i could use it like that:

Foo foo;

string myattr = "attr1";
string myval = "val x1";
string myval = "val x2";

setattribute( foo, myattr, myval1 );   // pseudocode... possible somehow?
cout << foo.attr1;     // prints "val x1"

setattribute( foo, myattr, myval2 );   // pseudocode... possible somehow?
cout << foo.attr1;     // prints "val x2"

The method i call in the loop could look like this…

// its_ref : empty string reference
// row: ptr on the current db row = query result object
// colname:  the db column = attribute
// ki: the object 

void get_fd( ITString & its_ref, ITRow * row, ITString colname, ns4__SOAPKunde& ki ) {
        ITConversions *c;
        ITValue *v = row->Column( colname );
        v->QueryInterface(ITConversionsIID, (void **) &c);
        c->ConvertTo( its_ref );
        // here is the place i want to use it :
        setattribute( ki, colname, its_ref.Data() );
}

Answer 1

You can use member data pointers. These can be of any type- e.g.

struct x {
    int y;
    int z;
};

int main() {
    int x::* res = &x::y;
}

However, if you want to start accessing them by identifier at runtime, you will have to build your own system from scratch.