mutable.cpp

来自「Thinking in C++ 2nd edition source code 」· C++ 代码 · 共 25 行

//: C08:Mutable.cpp
// From Thinking in C++, 2nd Edition
// at http://www.BruceEckel.com
// (c) Bruce Eckel 1999
// Copyright notice in Copyright.txt
// The "mutable" keyword

class Y {
  int i;
  mutable int j;
public:
  Y() { i = j = 0; }
  void f() const;
};

void Y::f() const {
//! i++; // Error -- const member function
    j++; // OK: mutable
}

int main() {
  const Y yy;
  yy.f(); // Actually changes it!
} ///:~