#include <iostream>
using namespace std;
 
template <typename T>
class has_foo
{
  typedef char yes;
  typedef long no;
 
  template <typename U, U> class signature_check;
  template <typename C> static yes test(signature_check<void (C::*)(int), &C::foo>*);
  template <typename C> static no test(...);
 
public:
  static const bool value = (sizeof(test<T>(0)) == sizeof(yes));
};
 
struct Base
{
	void foo(int);
};
 
struct Derived : public Base
{
};
 
 
int main() {
	cout << "Base: " << has_foo<Base>::value << endl;
	cout << "Derived: " << has_foo<Derived>::value << endl;
}

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