typenamedid.cpp

来自「Thinking in c++ 2nd edition,c++编程思想（第2版）」· C++ 代码 · 共 27 行

//: C05:TypenamedID.cpp {-bor}
// From "Thinking in C++, Volume 2", by Bruce Eckel & Chuck Allison.
// (c) 1995-2004 MindView, Inc. All Rights Reserved.
// See source code use permissions stated in the file 'License.txt',
// distributed with the code package available at www.MindView.net.
// Uses 'typename' as a prefix for nested types.

template<class T> class X {
  // Without typename, you should get an error:
  typename T::id i;
public:
  void f() { i.g(); }
};

class Y {
public:
  class id {
  public:
    void g() {}
  };
};

int main() {
  X<Y> xy;
  xy.f();
} ///:~