Assignment #4 solution

asmt4.cpp

#include <iostream>
#include <iomanip>
#include <cstdlib>
#include <string>
#include <fstream>

using namespace std;

const int WordListSize = 10000;
const int ParaWidth = 60;	// paragraph width

class WordList {
  private:
	string words[WordListSize];
	int nwords;

  public:
  	WordList(void);
  	int length();
  	string at(int);
  	void setAt(int, string);
  	
	bool readFrom(istream&);
	bool readFrom(string);
  	bool writeTo(string);
  	bool writeParaTo(ostream&);
  	bool writeParaTo(string);
  	void addWord(string);
  	bool hasWord(string);
};

WordList::WordList(void)
{
	nwords = 0;
}

int
WordList::length(void)
{
	return nwords;
}

string
WordList::at(int i)
{
	if(i < 0 || i >= WordListSize)
		return "";
	return words[i];
}

void
WordList::setAt(int i, string w)
{
	if(i < 0 || i >= WordListSize)
		return;
	words[i] = w;
}

bool
WordList::readFrom(istream &f)
{
	string w;
	
	nwords = 0;
	f >> w;
	while(f.good()){
		addWord(w);
		f >> w;
	}
	return true;
}

bool
WordList::readFrom(string filename)
{
	ifstream f;
	bool b;
	
	f.open(filename.c_str());
	if(f.fail())
		return false;
	b = readFrom(f);
	f.close();
	return b;
}

bool
WordList::writeTo(string filename)
{
	int i;
	ofstream f;
	
	f.open(filename.c_str(), ofstream::trunc);
	if(f.fail())
		return false;
	i = 0;
	while(f.good() && i < nwords){
		f << words[i] << endl;
		i++;
	}
	f.close();
	return true;
}

bool
WordList::writeParaTo(ostream &f)
{
	int i, n;
	string w;
	
	n = 0;
	for(i = 0; i < nwords; i++){
		w = words[i];
		n += w.length()+1;
		if(n > ParaWidth){
			f << endl;
			n = w.length()+1;
		}
		f << w << " ";
	}
	if(n > 0)
		f << endl;
	return true;
}

bool
WordList::writeParaTo(string filename)
{
	ofstream f;
	bool b;
	
	f.open(filename.c_str());
	if(f.fail())
		return false;
	b = writeParaTo(f);
	f.close();
	return b;
}

void
WordList::addWord(string w)
{
	if(w.length() == 0)
		return;
	if(nwords >= WordListSize){
		cout << "too many words" << endl;
		exit(1);
	}
	words[nwords] = w;
	nwords++;
}

bool
WordList::hasWord(string w)
{
	int i;
	
	for(i = 0; i < nwords; i++)
		if(words[i] == w)
			return true;
	return false;
}

bool
fileExists(string filename)
{
	ifstream f;
	bool b;
	
	f.open(filename.c_str());
	b = !f.fail();
	f.close();
	return b;
}

void
doParagraph(WordList &dict)
{
	int i, choice, yes;
	WordList ignore, para;
	string w, s, filename;
	
	cout << "Enter a paragraph (end it with EOF -- CTRL-z or CTRL-d):" << endl;
	para.readFrom(cin);
	cin.clear();
	cout << endl;
	
	for(i = 0; i < para.length(); i++){
		w = para.at(i);
		if(w.length() == 1 || ignore.hasWord(w) || dict.hasWord(w))
			continue;
		cout << "Incorrect word '" << w
			<< "' [1=accept, 2=change, 3=ignore once, 4=ignore]: ";
		cin >> choice;
		switch(choice){
		case 1:
			dict.addWord(w);
			break;
		case 2:
			cout << "Enter new word:";
			cin >> s;
			para.setAt(i, s);
			break;
		case 3:	// do nothing
			break;
		case 4:
			ignore.addWord(w);
			break;
		default:
			cout << "internal error" << endl;
			exit(1);
		}
	}
	cout << endl;
	cout << "Corrected paragraph:" << endl;;
	para.writeParaTo(cout);
	cout << endl;
	cout << "Save corrected paragraph? [1=yes, 0=no]: ";
	cin >> yes;
	if(yes){
		for(;;){
			cout << "Enter filename: ";
			cin >> filename;
			if(!fileExists(filename))
				break;
			cout << "file by that name already exists" << endl;
		}
		if(!para.writeParaTo(filename))
			cout << "failed to write paragraph to " << filename << endl;
	}
}

int
main(void)
{
	WordList dict, ignore, para;
	string dictname;
	int dlen, yes;
	
	cout << "Welcome!" << endl;
	cout << "Enter dictionary filename: ";
	cin >> dictname;
	
	if(!dict.readFrom(dictname)){
		cout << "failed to open dictionary file " << dictname << endl;
		exit(1);
	}
	dlen = dict.length();
	
	do{
		doParagraph(dict);
		cout << "Try another paragraph? [1=yes, 0=no]: ";
		cin >> yes;
	}while(yes);
	
	if(dict.length() > dlen && !dict.writeTo(dictname)){
		cout << "failed to write to dictionary file " << dictname << endl;
		exit(1);
	}
}