meme.cpp

meme.cpp

/*****************************************************
 * Name:			Tyler Beatty
 * Date Created:	2015-04-16
 * Date Modified:	2015-04-17
 * Lab Number:		Programming Exercise 2
 * Filename:		PE 2 Tyler Beatty.cpp
 * 
 * Input:
 *	A text file named "cosby.txt"
 * 
 * Output:
 *	The counts of the occurances of each word in said
 *	text file, formatted like so:
 *		Word       Frequency
 *		I          1
 *		don't      1
 *		know       1
 *		the        2
 *		key        2
 *		[...]
 *****************************************************/

#define _CRT_SECURE_NO_WARNINGS		// allow visual studio to use strcpy

// Memory Leak Checker
#include <crtdbg.h> 
#define _CRTDBG_MAP_ALLOC

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

using std::cout;
using std::cerr;
using std::endl;
using std::ifstream;
using std::strcpy;
using std::setw;
using std::left;

const int BUFFER_LENGTH = 256;

// NOTE: variables are passed by POINTER
// adds the word to the dynamic arrays storing the words & the word counts
void ProcessWord(char * buffer, int wordLength, char *** words, int ** wordCounts, int * numWords);
// frees the memory used by the arrays
void Purge(char *** words, int ** wordCounts, int * numWords);
// reads a word into a buffer, returns the length of the word
int ReadWord(ifstream & file, char * buffer, int bufferLength);
// prints the contents of the arrays
void PrintArrays(char ** words, int * wordCounts, int numWords);

int main()
{
	_CrtSetDbgFlag(_CRTDBG_ALLOC_MEM_DF | _CRTDBG_LEAK_CHECK_DF);

	ifstream file("cosby.txt");

	if (!file.is_open())
	{
		cerr << "Error: Couldn't open cosby.txt!" << endl;
		return -1;
	}

	char ** words = nullptr;
	int * wordCounts = nullptr;
	int numWords = 0;

	char buffer[BUFFER_LENGTH];
	buffer[0] = '\0';

	while (!file.eof())
	{
		int wordLength = ReadWord(file, buffer, BUFFER_LENGTH);
		if (wordLength > 0)
			ProcessWord(buffer, wordLength, &words, &wordCounts, &numWords);
	}

	PrintArrays(words, wordCounts, numWords);

	Purge(&words, &wordCounts, &numWords);

	return 0;
}

void ProcessWord(char * buffer, int wordLength, char *** words, int ** wordCounts, int * numWords)
{
	// find the index of where a word matches with an already stored word if that's the case
	int matchIndex = -1;
	for (int i = 0; i < *numWords; i++)
	{
		if (_stricmp(buffer, (*words)[i]) == 0)
			matchIndex = i;
	}

	if (matchIndex != -1)
	{
		(*wordCounts)[matchIndex] += 1;						// increment the count of the word
	}
	else													// insert the word
	{
		char ** temp_words = new char *[*numWords + 1];		// resize the arrays
		int * temp_wordCounts = new int[*numWords + 1];

		for (int i = 0; i < *numWords; i++)					// transfer the old words & word counts into the new array
		{
			temp_words[i] = (*words)[i];
			temp_wordCounts[i] = (*wordCounts)[i];
		}

		delete[] * words;									// delete the old, smaller arrays
		delete[] * wordCounts;

		*words = temp_words;								// let the new arrays replace the (now deleted) old ones
		*wordCounts = temp_wordCounts;

		(*words)[*numWords] = new char[wordLength + 1];		// create the new string
		strcpy((*words)[*numWords], buffer);

		(*wordCounts)[*numWords] = 1;						// set the new string's associated count at 1

		(*numWords)++;
	}
}

void Purge(char *** words, int ** wordCounts, int * numWords)
{
	for (int i = 0; i < *numWords; i++)		// deallocate the strings referenced by the pointers
		delete[](*words)[i];
	delete[] * words;						// deallocate the array of pointers
	delete[] * wordCounts;					// deallocate the array of ints

	*words = nullptr;						// reset the values
	*wordCounts = nullptr;
	*numWords = 0;
}

int ReadWord(ifstream & file, char * buffer, int bufferLength)
{
	char currentChar;
	int stringLength = 0;

	while ( stringLength < (bufferLength - 1) &&			// Checks if there's enough room in the buffer
			file.get(currentChar) &&						// Reads a character from the file
			((currentChar >= 'a' && currentChar <= 'z') ||	// Checks if the character is part of a word
			 (currentChar >= 'A' && currentChar <= 'Z') ||
			 (currentChar == '-') ||
			 (currentChar == '\'')) )
	{
		buffer[stringLength] = currentChar;					// Appends the character to the buffer string
		stringLength++;
	}
	buffer[stringLength] = '\0';							// Terminates the buffer string

	return stringLength;
}

void PrintArrays(char ** words, int * wordCounts, int numWords)
{
	cout << left
		<< "Word Frequency Analysis" << endl << endl
		<< setw(10) << "Word" << " Frequency" << endl;
	for (int i = 0; i < numWords; i++)
		cout << setw(10) << words[i] << " " << wordCounts[i] << endl;
}