pmem2.cpp

来自「Thinking in C++ 2nd edition source code 」· C++ 代码 · 共 36 行

//: C11:Pmem2.cpp
// From Thinking in C++, 2nd Edition
// at http://www.BruceEckel.com
// (c) Bruce Eckel 1999
// Copyright notice in Copyright.txt
// Pointers to members
#include <iostream>
using namespace std;

class Widget {
  void f(int) const {cout << "Widget::f()\n";}
  void g(int) const {cout << "Widget::g()\n";}
  void h(int) const {cout << "Widget::h()\n";}
  void i(int) const {cout << "Widget::i()\n";}
  enum { count = 4 };
  void (Widget::*fptr[count])(int) const;
public:
  Widget() {
    fptr[0] = &Widget::f; // Full spec required
    fptr[1] = &Widget::g;
    fptr[2] = &Widget::h;
    fptr[3] = &Widget::i;
  }
  void select(int I, int J) {
    if(I < 0 || I >= count) return;
    (this->*fptr[I])(J);
  }
  int Count() { return count; }
};

int main() {
  Widget w;
  for(int i = 0; i < w.Count(); i++)
    w.select(i, 47);
} ///:~