inheritstack2.cpp

Think in C++ 第二版源码

//: C14:InheritStack2.cpp
// From Thinking in C++, 2nd Edition
// Available at http://www.BruceEckel.com
// (c) Bruce Eckel 1999
// Copyright notice in Copyright.txt
//{L} ../C13/Stack4
// Composition vs. inheritance
#include "../C13/Stack4.h"
#include "../require.h"
#include <iostream>
#include <fstream>
#include <string>
using namespace std;

class StringList {
  Stack stack; // Embed instead of inherit
public:
  void push(string* str) {
    stack.push(str);
  }
  string* peek() const {
    return (string*)stack.peek();
  }
  string* pop() {
    return (string*)stack.pop();
  }
};

int main() {
  ifstream file("InheritStack2.cpp");
  assure(file, "InheritStack2.cpp");
  string line;
  StringList textlines;
  while(getline(file,line))
    textlines.push(new string(line));
  string* s;
  while((s = textlines.pop()) != 0) // No cast!
    cout << *s << endl;
} ///:~