wordcount.cpp

C++编程思想第二版第一册答案

//: C20:WordCount.cpp
// From Thinking in C++, 2nd Edition
// Available at http://www.BruceEckel.com
// (c) Bruce Eckel 1999
// Copyright notice in Copyright.txt
//{L} StreamTokenizer
// Count occurrences of words using a map
#include "StreamTokenizer.h"
#include "../require.h"
#include <string>
#include <map>
#include <iostream>
#include <fstream>
using namespace std;

class Count {
  int i;
public:
  Count() : i(0) {}
  void operator++(int) { i++; } // Post-increment  
  int& val() { return i; }
};

typedef map<string, Count> WordMap;
typedef WordMap::iterator WMIter;

int main(int argc, char* argv[]) {
  requireArgs(argc, 1);
  ifstream in(argv[1]);
  assure(in, argv[1]);
  StreamTokenizer words(in);
  WordMap wordmap;
  string word;
  while((word = words.next()).size() != 0)
    wordmap[word]++;
  for(WMIter w = wordmap.begin(); 
      w != wordmap.end(); w++)
    cout << (*w).first << ": "
      << (*w).second.val() << endl;
} ///:~