Simple hangman win32 console application

Hangman

// Hangman.cpp : Defines the entry point for the console application.
//

//Leah Loughran, 2012
//Simple Hangman console game

#include "stdafx.h"
#include <iostream>
#include <string>
#include <vector>
#include <ctype.h>
#include <algorithm>
#include <ctime>

using namespace std;

void printHangman(int chancesLeft)
{
	switch (chancesLeft)
	{
	case 5:
		cout << "  ____   " << endl;
		cout << " |    |  " << endl;
		cout << " |       " << endl;
		cout << " |       " << endl;
		cout << " |       " << endl;
		cout << "_|___    " << endl;
		cout << endl;
		break;
	case 4:
		cout << "  ____   " << endl;
		cout << " |    |  " << endl;
		cout << " |    O  " << endl;
		cout << " |       " << endl;
		cout << " |       " << endl;
		cout << "_|___    " << endl;
		cout << endl;
		break;
	case 3:
		cout << "  ____   " << endl;
		cout << " |    |  " << endl;
		cout << " |   _O_ " << endl;
		cout << " |       " << endl;
		cout << " |       " << endl;
		cout << "_|___    " << endl;
		cout << endl;
		break;
	case 2:
		cout << "  ____   " << endl;
		cout << " |    |  " << endl;
		cout << " |   _O_ " << endl;
		cout << " |    |  " << endl;
		cout << " |       " << endl;
		cout << "_|___    " << endl;
		cout << endl;
		break;
	case 1:
		cout << "  ____   " << endl;
		cout << " |    |  " << endl;
		cout << " |   _O_ " << endl;
		cout << " |    |  " << endl;
		cout << " |   /   " << endl;
		cout << "_|___    " << endl;
		cout << endl;
		break;
	case 0:
		cout << "  ____   " << endl;
		cout << " |    |  " << endl;
		cout << " |   _O_ " << endl;
		cout << " |    |  " << endl;
		cout << " |   / \\ " << endl;
		cout << "_|___    " << endl;
		cout << endl;
		break;
	}
	//depending on the number of chances left (1-5), print out a gallows with a guy hanging
}

void printWord(string word, vector<char> revealedLetters)
{
	//go through each character in the word; if that character is found in "revealedLetters", then print the letter, else print blank
	for (int i = 0; i < word.length(); i++)
	{
		if (count(revealedLetters.begin(), revealedLetters.end(), word[i]) > 0) //the character is found in "revealedLetters"
		{
			cout << char(toupper(word[i])) << " "; //print the uppercase letter
		}
		else //the character is not found
		{
			cout << "__ "; //print a blank
		}
	}
	cout << endl;
}

bool letterExists(string word, char letter)
{
	//check if the letter exists in the word
	bool exists = false;
	for (int i = 0; i < word.length(); i++) //go through each character in the word
	{
		if (word[i] == letter) //check if that character matches the letter we're looking for
		{
			exists = true; //set it to true
		}
	}
	return exists;
}

int numOfUniqueLetters(string word)
{
	//calculates the number of unique letters in a word
	vector<char> uniqueLetters;
	for (int i = 0; i < word.length(); i++)
	{
		if (!(count(uniqueLetters.begin(), uniqueLetters.end(), word[i]) > 0)) //if it's not already in there
		{
			uniqueLetters.push_back(word[i]);
		}
	}

	return (int)uniqueLetters.size();
}

int _tmain(int argc, _TCHAR* argv[])
{
	cout << "Welcome to Hangman!" << endl;

	vector<string> dictionary; //putting random words in the dictionary...
	//not very pretty but basic enough for beginners to understand
	//note: this program does not works with multi-word phrases
	dictionary.push_back("biscuit");
	dictionary.push_back("alarming");
	dictionary.push_back("microscopic");
	dictionary.push_back("memorable");
	dictionary.push_back("yellow");
	dictionary.push_back("jacket");
	dictionary.push_back("bumblebee");
	dictionary.push_back("purse");
	dictionary.push_back("pencil");
	dictionary.push_back("genes");
	dictionary.push_back("programming");
	dictionary.push_back("technology");
	dictionary.push_back("keyboard");
	dictionary.push_back("tabby");
	dictionary.push_back("cupboard");

	vector<char> guessedLetters;
	vector<char> successfulLetters;

	string playAgain = "y";
	while (playAgain == "y")
	{
		srand(time(NULL));
		int randomSpot = (rand()%(dictionary.size())); //gets a random spot in the dictionary
		string randomWord = dictionary[randomSpot]; //gets a random word from the dictionary

		int chances = 5; //starts the game with 5 chances to guess

		while ((chances > 0)&&(successfulLetters.size() != numOfUniqueLetters(randomWord))) //continue getting guesses until the player runs out of chances
		{
			cout << "\n\n" << endl;
			printHangman(chances); //print the gallows
			printWord(randomWord, successfulLetters); //print the word in its currently revealed state

			char guess = '1'; //start guess out as the number 1
			while (!isalpha(guess)) //guess is not a letter
			{
				cout << "Please enter a letter to guess! You have " << chances << " chance(s) left." << endl;
				cin >> guess;
				guess = tolower(guess); //make sure the guess is lowercase
				if (!isalpha(guess)) //if it's still not a letter, prompt the user to guess again
				{
					cout << "Your guess is not a letter; guess again" << endl;
				}
				else if (count(guessedLetters.begin(), guessedLetters.end(), guess) > 0) //if the letter has already been guessed
				{
					cout << "You have already guessed that; guess again" << endl;
				}
				else
				{
					guessedLetters.push_back(guess); //the guess is valid; add the guess to the list of guessed letters
					if (letterExists(randomWord, guess)) //if the letter is found in the word
					{
						cout << "Great guess! That letter is found in the word." << endl;
						successfulLetters.push_back(guess); //add the letter to the list of successful guesses
					}
					else //the letter does not exist in the word
					{
						cout << "Sorry, your guess was not found in the word!" << endl;
						chances--; //they lost one chance to guess
					}
				}
			}
		}

	/*if they're out of the loop, that either means:
		1) chances == 0
			-THEY LOST
		2) successfulLetters.size() == numOfUniqueLetters(randomWord)
			-THEY WON
	*/

		if (chances == 0) //player lost
		{
			printHangman(0);
			cout << "Sorry, you lost Hangman! The word was \"" << randomWord << "\"." << endl;
		}
		else if (successfulLetters.size() == numOfUniqueLetters(randomWord))
		{
			cout << "Congratulations! You won Hangman by correctly guessing the word \"" << randomWord << "\"." << endl;
		}

		playAgain = "foo"; //reset playAgain
		while (!((playAgain == "y")||(playAgain == "n")))
		{
			cout << "Would you like to play again? Enter y for yes or n for no." << endl;
			cin >> playAgain;
			if (!((playAgain == "y")||(playAgain == "n"))) //invalid input
			{
				cout << "Invalid input; try again" << endl;
			}
		}
	}

	return 0;
}