applist.cpp

Thinking in C++ 2nd edition source code which are all the cores of the book Thinking in C++ second e

//: C16:Applist.cpp
// From Thinking in C++, 2nd Edition
// at http://www.BruceEckel.com
// (c) Bruce Eckel 1999
// Copyright notice in Copyright.txt
// Apply a function to a TStack
#include <iostream>
#include "TStack.h"
using namespace std;

// 0 arguments, any type of return value:
template<class T, class R>
void applist(TStack<T>& tl, R(T::*f)()) {
  TStackIterator<T> it(tl);
  while(it) {
    (it.current()->*f)();
    it++;
  }
}

// 1 argument, any type of return value:
template<class T, class R, class A>
void applist(TStack<T>& tl, R(T::*f)(A), A a) {
  TStackIterator<T> it(tl);
  while(it) {
    (it.current()->*f)(a);
    it++;
  }
}

// 2 arguments, any type of return value:
template<class T, class R, class A1, class A2>
void applist(TStack<T>& tl, R(T::*f)(A1, A2),
    A1 a1, A2 a2) {
  TStackIterator<T> it(tl);
  while(it) {
    (it.current()->*f)(a1, a2);
    it++;
  }
}

// Etc., to handle maximum probable arguments

class Gromit { // The techno-dog
  int arf;
public:
  Gromit(int Arf = 1) : arf(Arf + 1) {}
  void speak(int) {
    for(int i = 0; i < arf; i++)
      cout << "arf! ";
    cout << endl;
  }
  char eat(float) {
    cout << "chomp!" << endl;
    return 'z';
  }
  int sleep(char, double) {
    cout << "zzz..." << endl;
    return 0;
  }
  void sit(void) {}
};

int main() {
  TStack<Gromit> dogs;
  for(int i = 0; i < 5; i++)
    dogs.push(new Gromit(i));
  applist(dogs, &Gromit::speak, 1);
  applist(dogs, &Gromit::eat, 2.0f);
  applist(dogs, &Gromit::sleep, 'z', 3.0);
  applist(dogs, &Gromit::sit);
} ///:~