how to declare a generic class in c++

Question

My main question is: can I put the generic type before a class definition?

Like, can I do something like this:

generic class Classname (ParameterType parameter)
{
     cout << "Hello world";
}

What is this "`generic` type"? Is `generic` supposed to be a keyword? (It's not a keyword in C++.) — JaMiT, Dec 07 '19 at 23:38
related: https://stackoverflow.com/questions/388242/the-definitive-c-book-guide-and-list — UKMonkey, Dec 07 '19 at 23:40
Your question is unclear. What do you mean by a "generic" type? What do you expect to be able to do with such a type? Without such clarification - in your question - there is no way to judge if any answer given is useful or even relevant. — Peter, Dec 08 '19 at 01:00
Your code snippet looks like a function, not a class. A class has no parameters and no function body. — Thomas Sablik, Dec 08 '19 at 02:38

bhristov · Answer 1 · 2019-12-07T23:41:20.173

3

Templates are the way to do generics in C++. You can write it like this:

template<class ItemType> class ClassName
{
public:
   ClassName(const ItemType& newdata) : data(newdata) {}
private:
   ItemType data;
};

Later on in main:

ClassName<int> data1(1);
ClassName<char> data2('A');

edited Dec 07 '19 at 23:41

answered Dec 07 '19 at 23:34

bhristov

While what you say here is correct, the original question is so unclear, it is not possible to even determine if this answer addresses the question. – Peter Dec 08 '19 at 00:58
I know. I am just giving him an example of what generics looks like in C++. – bhristov Dec 08 '19 at 01:34

1 Answers1