Converting C++ code to html

 The C++ code (yes, it's primitive,I know) I presented in my last
entry was not formatted attractively. So I researched the web for
a C++ to html formatter (in C++). I pretty soon found it in one of
the examples in the boost library regex documentation. After some
modifications,I got it to format the previous C++ code. It looks
nicer now (but it's still novice level). Here's the output:

#include <iostream>
#include <fstream>
#include <string>
#include <map>
#include <set>
#include <cctype>

#include <boost/tokenizer.hpp>
#include <boost/regex.hpp>

using namespace std;
using namespace boost;

map<string,int> model;


void toLower(basic_string<char> &s) {
 for (basic_string<char>::iterator p = s.begin(); 
      p != s.end(); ++p) {
      *p = tolower(*p);
 }
}

map<string,int> train_model(string filename) {
 
 ifstream in(filename.c_str());
 
 string tmp;
 regex re("[a-zA-Z]+");
 map<string,int> model;

 while(!in.eof()) {
  getline(in, tmp, '\n');
  tokenizer<> tok(tmp);
  for(tokenizer<>::iterator beg=tok.begin(); beg!=tok.end();++beg){
    if (regex_match(*beg, re))  {
     string t(*beg);
     toLower(t);
     model[t]++;
    }
  }
 } 
 return model;
}

set<string> edit1(string w) {
 set<string> edit1set;

int word_len = w.length();
 string alphabet("abcdefghijklmnopqrstuvwxyz");
 
 //deletion
 for(int i = 0; i < word_len; ++i) 
   edit1set.insert(w.substr(0,i) + w.substr(i+1,word_len));
 
 //transposition

 for(int i = 0; i < word_len-1; ++i) 
   edit1set.insert(w.substr(0,i) + w[i+1] + w[i]  + w.substr(i+2,word_len));
 
 // alteration 

 for(int i = 0; i < word_len; ++i) {
   for(string::iterator si=alphabet.begin(); si != alphabet.end(); ++si) { 
     edit1set.insert(w.substr(0,i) + *si + w.substr(i+1,word_len));   
   }
 }
 
 //insertion

 for(int i = 0; i < word_len+1; ++i) {
   for(string::iterator si=alphabet.begin(); si != alphabet.end(); ++si) { 
     edit1set.insert(w.substr(0,i) + *si + w.substr(i,word_len));       }
 }
return edit1set;
}

set<string> known_edit2(string w) {
 set<string> ed2;
 
 set<string> ed1 = edit1(w);
 for(set<string>::iterator si = ed1.begin(); si != ed1.end(); ++si) {
    set<string> tmp = edit1(*si);
   
   for(set<string>::iterator si2 = tmp.begin(); si2 !=tmp.end(); ++si2) {
       if(model.find(*si2) != model.end())  ed2.insert(*si2);
   }   
 }
 return ed2;
}

set<string> known(set<string> words) {
set<string> known_set;
 for(set<string>::const_iterator si = words.begin(); si != words.end(); ++si) {
       if(model.find(*si) != model.end())  known_set.insert(*si);
 }

return known_set;
}

string correct(string word) {

set<string> candidates;
set<string> w;
w.insert(word);

if((candidates = known(w)).size() == 0) {
 if((candidates = known(edit1(word))).size() == 0){
  if((candidates = known(known_edit2(word))).size() == 0) {
    return word;
  }
 } 
}


int cur_max = 0;
string tmp;
for(set<string>::const_iterator si = candidates.begin(); si !=candidates.end(); ++si) {
 if(model[*si] > cur_max) {
    cur_max = model[*si];
    tmp = *si;
 }
}
return tmp;
}

int main(int argc, char** argv) {

model = train_model("big.txt");

string input;
 while (1) {
  cout << "Testing correct(), enter a word: ";
  cin >> input;
  cout << "correct(" << input << ")" << " returns " << correct(input) << '\n';
 }
}