具有模板化和非模板化形式的C ++类

Question

I am curious if it is possible to have a class with both a templated and non-templated form. Something like:

SomeClass foo;
SomeClass<int> bar;

foo.do_something();
bar.do_something(5);

I am fine defining everything more than once, but I don't know if it's possible to use the same class name.

Answer 1

Short answer: no, it's not allowed. The exact error message your compiler gives you will vary, but you should get an error message.

You can, however, provide default parameters for a template, so you can instantiate it with only <> , like:

template <class T=int>
class X {};

int main(){ 
    X<long> a;
    X<>     b; // used default, so equivalent to "X<int> b;"
}

Answer 2

You can get something close, by using default template parameters:

template <class T = char>
class SomeClass{};

SomeClass<> foo;     // char type
SomeClass<int> bar;  // int type

Use specialization if you want different behaviour for the default type's member functions.