/*
This code is designed to sort text only, and only text in upper
case letters. 
*/


#include <iostream>
#include <string>
#include <vector>
#include <list>
#include <fstream>


using namespace std;

typedef list<string> stringlist;

// will only work on upper case letters
void bucketSort(vector<string> & words, int pos) {
    int i;
    int j;
    int index;
    list<string>::iterator k;
    vector<stringlist> buckets (27);
    // bin 26 is reserved for strings shorter than the current length

    // push all of the words into the right bins
    for(i=0;i<words.size();i++) {
         if(words[i].size() <= pos) {
	     buckets[26].push_back(words[i]);
	 } else {
	     index = int(words[i][pos] -'A');
             buckets[index].push_back(words[i]);
	 }
    }

    // take them out of the bins and put them back into the list
    j = 0;
    for(i=0;i<=26;i++) {
        for(k=buckets[i].begin();k!=buckets[i].end();k++) {
	    words[j] = *k;
	    j++;
	}
    }
}


int main () {
    vector<string>words;   // the list to sort
    int i,j;
    ifstream infile;  
    string tmp;            
    int longest;           // the length of the longest string

    infile.open("data");

// read in the data
    longest = 0;
    infile >> tmp;
    while(infile) {
        // keep track of the length of the longest string
        if (tmp.size() > longest) {
	   longest = tmp.size();
	}

	//insert the word into the list
        words.push_back(tmp);
	infile >> tmp;
    }
    infile.close();

    // the radix sort
    for(j=longest-1;j>=0;j--) {
        // call to bucket sort
        bucketSort(words,j); 

        // print the list so far
	cout << "Sorting on position " << j << endl;
        for(i=0;i<words.size();i++) {
           cout << words[i] << endl;
        }
	cout << endl << endl << endl;

    }
}