C++ equivalent of using for a java parameter/return type

Question

In java, to make a function that returns an object that is the same type as a parameter and extends a certain class, I would type:

Answer 1

Also wondered the same question, that's a C++20 approach through concepts.

#include 
#include 
#include 
using namespace std;

class MyClass
{
    public:
        inline virtual void Print() const noexcept { cout << "Myclass" << endl; }  
};  


class Derived : public MyClass
{
    public:
        inline virtual void Print() const noexcept override { cout << "Derived" << endl; }  
};  


class NotDerived
{};

Create a concept with name CheckType which is satisfied when the concept's parameter Type is a BaseClass or a DerivedClass : BaseClass.

template 
concept CheckType = std::is_base_of::value;

Create a generic class where the T type REQUIRES to be MyClass or Derived : MyClass type.

template 
requires CheckType
class OnlyMyClass
{
    private:
        T Instance;

    public:
        inline void Print() const noexcept { Instance.Print(); }    // Print
};  


int main()
{
    //OnlyMyClass O1; // error, the associated constraints are not satisfied.
    OnlyMyClass    O2; // nice!
    OnlyMyClass    O3; // nice!
    O2.Print();
    O3.Print();
    
    return 0;
}   // main