isDerived: feel difference
C++

class base { public: int i; };
class child : public base { public: int j; };
class other { public: int z; };

template <typename D, typename B>
class IsDerived
{
	struct No {}; struct Yes { No no[2]; };
	static Yes Test(B*);
	static No Test(...);

public: enum { Derived = sizeof(Test(static_cast<D*>(0))) == sizeof(Yes) };
};

template <class T>
bool function()
{
	if (IsDerived<T, base>::Derived == 1)
		return true;
	else
		return false;
}


int _tmain(int argc, _TCHAR* argv[])
{
	assert(true == function<base>());
	assert (true == function<child>());
	assert (false == function<other>());
	assert (false == function<int>());

	return 0;
}

class Program
{
    class base_ { public int i; }
    class child : base_ { public int j; }
    class other { public int z; }

    static bool function<T>() where T : new()
    {
        T t = new T();
        if (t is base_)
            return true;
        else
            return false;
    }

    static void Main(string[] args)
    {
        Debug.Assert(true == function<base_>());
        Debug.Assert(true == function<child>());
        Debug.Assert(false == function<other>());
        Debug.Assert(false == function<int>());
    }
}