overhead.cpp

来自「Thinking in C++ 2nd edition source code 」· C++ 代码 · 共 43 行

//: C22:Overhead.cpp
// From Thinking in C++, 2nd Edition
// at http://www.BruceEckel.com
// (c) Bruce Eckel 1999
// Copyright notice in Copyright.txt
// Virtual Base class overhead
#include <fstream>
using namespace std;
ofstream out("overhead.out");

class Base {
public:
  virtual void f() const {};
  virtual ~Base() {}
};

class NonVirtualInheritance
  : public Base {};

class VirtualInheritance
  : virtual public Base {};

class VirtualInheritance2
  : virtual public Base {};

class MI
  : public VirtualInheritance,
    public VirtualInheritance2 {};

#define WRITE(arg) \
out << #arg << " = " << arg << endl;

int main() {
  Base b;
  WRITE(sizeof(b));
  NonVirtualInheritance nonv_inheritance;
  WRITE(sizeof(nonv_inheritance));
  VirtualInheritance v_inheritance;
  WRITE(sizeof(v_inheritance));
  MI mi;
  WRITE(sizeof(mi));
} ///:~