Thread: maps and populating from a batch?

My recent posts have revolved around this concept.
Text file, like html, is input and result needs to be a list of distinct words with a wordcount.

Distinct words with count is easy with a map. The problem I had was that I didn't have an easy way to drop out symbols and numbers. That's when I happened on this tokeniterator code.

I modified it from an input source to a stringstream to fit my need.

This last part of the code (see notes in code) then populates a vector with the culled list of all non-distinct words from wordIter. I want to write out wordIter to a map instead of a vector to get a distinct list.

How can I copy wordIter, which is the collection of data, to my map? I don't think I can loop through it with a traditional mapname[value]++.

NOTE: wordIter is noted to reference pred and predicate.

Code:

//: C20:TokenIteratorTest.cpp
#include <fstream>
#include <iostream>
#include <vector>
#include "TokenIterator.h"
#include <sstream>
#include <map>

using namespace std;


int main() {

	map<string, int> freq;
	std::string newword;
	//passing data as stream
	std::stringstream oss;
	//example defines string
	oss << "bunch of words";
    std::ostream_iterator<std::string> out(std::cout, "\n");
	typedef std::istreambuf_iterator<char> IsbIt;
	IsbIt begin(oss), isbEnd;
	Delimiters delimiters(" \t\n~;()\"<>:{}[]+-=&*#.,/\\0123456789");
	//strips out delimiters from string and produces a list of words (wordIter)
	TokenIterator<IsbIt, Delimiters> wordIter(begin, isbEnd, delimiters), end;
	//here is where I'm confused.
	//The below code populates a vector with the results.
	std::vector<std::string> wordlist;
	std::copy(wordIter, end, std::back_inserter(wordlist));
	std::copy(wordlist.begin(), wordlist.end(), out);
	//instead of populating a vector, I want to populate a map
	//so I can make the word list a distinct list with word count.



}

//: C20:TokenIterator.h
#ifndef TOKENITERATOR_H
#define TOKENITERATOR_H
#include <string>
#include <iterator>
#include <algorithm>
#include <cctype>

struct Isalpha { 
  bool operator()(char c) { 
    return isalpha(c); 
  }
};

class Delimiters {
  std::string exclude;
public:
  Delimiters() {}
  Delimiters(const std::string& excl) 
    : exclude(excl) {}
  bool operator()(char c) {
    return exclude.find(c) == std::string::npos;
  }
};

template <class InputIter, class Pred = Isalpha>
class TokenIterator: public std::iterator<
  std::input_iterator_tag,std::string,ptrdiff_t>{
  InputIter first;
  InputIter last;
  std::string word;
  Pred predicate;
public:
  TokenIterator(InputIter begin, InputIter end, 
    Pred pred = Pred()) 
    : first(begin), last(end), predicate(pred) {
      ++*this; 
  }
  TokenIterator() {} // End sentinel
  // Prefix increment:
  TokenIterator& operator++() {
    word.resize(0);
    first = std::find_if(first, last, predicate);
    while (first != last && predicate(*first))
      word += *first++;
    return *this;
  }
  // Postfix increment
  class Proxy { 
    std::string word;
  public:
    Proxy(const std::string& w) : word(w) {}
    std::string operator*() { return word; } 
  };
  Proxy operator++(int) { 
    Proxy d(word);
    ++*this; 
    return d; 
  }
  // Produce the actual value:
  std::string operator*() const { return word; }
  std::string* operator->() const {
    return &(operator*()); 
  }
  // Compare iterators:
  bool operator==(const TokenIterator&) { 
    return word.size() == 0 && first == last; 
  }
  bool operator!=(const TokenIterator& rv) { 
    return !(*this == rv);
  }
};
#endif // TOKENITERATOR_H ///:~