instrument.cpp

来自「thingking in c++（C++编程思想） 各章节课后练习的答案」· C++ 代码 · 共 27 行

//: C14:Instrument.cpp
// From Thinking in C++, 2nd Edition
// Available at http://www.BruceEckel.com
// (c) Bruce Eckel 2000
// Copyright notice in Copyright.txt
// Inheritance & upcasting
enum note { middleC, Csharp, Cflat }; // Etc.

class Instrument {
public:
  void play(note) const {}
};

// Wind objects are Instruments
// because they have the same interface:
class Wind : public Instrument {};

void tune(Instrument& i) {
  // ...
  i.play(middleC);
}

int main() {
  Wind flute;
  tune(flute); // Upcasting
} ///:~