How can I declare a template pointer without knowing the type?

Question

This is what I would like to do:

ExampleTemplate* pointer_to_template;
cin >> number;
switch (number) {
case 1:
    pointer_to_template = new ExampleTempla         


        

Answer 1

You can't. ExampleTemplate and ExampleTemplate are two different, unrelated types. If you always have a switch over several options, use boost::variant instead.

typedef boost::variant, Example> ExampleVariant;
ExampleVariant v;
switch (number) {
    case 1: v = Example(); break;
    case 2: v = Example(); break;
}
// here you need a visitor, see Boost.Variant docs for an example

Another way is to use an ordinary base class with virtual public interface, but I'd prefer variant.

struct BaseExample {
    virtual void do_stuff() = 0;
    virtual ~BaseExample() {}
};

template 
struct Example : BaseExample { ... };

// ..
BaseExample *obj;