// CSE 143 Au00  HW1 Sample Solution
// HP  9/00

// main.cpp - Main program and string processing functions

#include <iostream>
#include <fstream>
#include <string>
#include <cctype>
using namespace std;

#include "wordlist.h"

const int MAX_FILENAME_LENGTH = 300;	// longest input file name

// = copy of s with all punctuation removed
// (punctuation as defined by ispunt() in cctype)
string strip_punctuation(string s) {
	string result = "";
	for (int k = 0; k < s.length(); k++)
		if (!ispunct(s[k]))
			result += s[k];

	return result;
}


// = copy of s with all upper-case characters converted to lower-case
string lower_case(string s) {

	for (int k = 0; k < s.length(); k++)
		s[k] = tolower(s[k]);

	return s;
}


// Read file name, open file, read and count words in the file, then
// print the most frequent words in order of decreasing frequency.
// Number of words to be printed is also requested from the user.
int main() {
	char fn[MAX_FILENAME_LENGTH];	// input file name
	string word;					// current word from input file
	WordList word_list;				// list of word/frequency pairs
	int nWords_to_print;			// # words to be printed

	cout << "Please enter file name: ";
	cin >> fn;

	// open input file; exit if this fails
	ifstream infile(fn);
	if (!infile) {
		cout << "unable to open input file" << endl;		
		return 1;

	}

	// read words and add to word_list
	make_empty(word_list);
	while (infile >> word) {
		word = lower_case(strip_punctuation(word));
		if (word.length() > 0)
			count_word(word, word_list);
	}

	// get number of words to print from user
	cout << "How many word/frequency pairs do you want? ";
	cin >> nWords_to_print;

	// print word/frequency pairs in order
	sort_words(word_list);
	print_n_words(nWords_to_print, word_list);

	return 0;
}