//------------------------------------------------------------
//
// x.459 Assignment #2 sample solution
// 28-Feb-1997
// Michael Wolfe
// 
// This program is an example solution for the "guess a word"
// assignment for class on Feb. 24.  It illustrates (I hope)
// some elements of good style, but should be treated as one
// of many possible solutions.
//
// Note:  the major things this should illustrate are:
//
// o Break your program up into small functions which do very
// well-defined pieces of work.  Pass values between them
// and avoid using global variables except for constants.
//
// o Use understandable function and variable names.
//
// o No "magic numbers".  Turn constant values into #DEFINE
// or global const values.  Use MAXWORDLENGTH as an example.
//
// o Comment enough, but not too much.  Explain any strange code,
// and document towards your intended audience.  My audience here
// is the x.459 class, so I am writing the comment with that in
// mind.
//
// o Don't declare extra variables unless they are needed
// to help readability and clarify logic.
//
// o I'm using 'flush' in the output because people seem to
// keep having trouble with output not being flushed in the VC++
// environment.
//
//------------------------------------------------------------


// Needed for stream i/o (cin and cout)
#include <iostream.h>

// Needed for random number functions
#include <stdlib.h>

// Needed for string functions
#include <string.h>

// Needed for time function used by random number seeding
#include <time.h>


//
// Words to choose from.  Note:  in a "real" solution
// these would probably be read from a dictionary on disk.
// We haven't learned file I/O yet, so we'll do it this way.
// We would like to avoid this as a global variable in the
// future.
//
char* words[] = 
{	
	"steatopygic",
	"limoscene",
	"obsequious",
	"pusillanimous",
	"obfuscate" 
};


//
// Constant defining the number of words.  Would have
// used #define if this were C, but we'll use 'const int'
// here instead.  We haven't learned this yet, but we will.
//
const int NUMWORDS = 5;


//
// The longest that we will allow user input to be.
//
const int MAXWORDLENGTH = 30;


//
// Give the user the game instructions
//
void userInstructions()
{
	cout << "Hello!  We are going to play the 'guess a word'" << endl;
	cout << "game, which should keep you entertained for hours" << endl;
	cout << "on end.  I will choose a word and tell you how" << endl;
	cout << "many characters it is.  You will then guess the" << endl;
	cout << "word until you get it right.  I will give you clues" << endl;
	cout << "based on how many characters you got correct." << endl;
	cout << endl << flush;
}


// 
// Choose a word.  Generate a random number and pick the right
// word in the global word array to use.  Here we can return
// a char* because we are returning a pointer to a word that
// has already been defined globally.  
//
// Note: this is a good example of a place where it is better
// not to declare extra variables.  The fact that this routine
// could be written in one line makes it more efficient and
// doesn't sacrifice readability too badly.
//
char* chooseWord()
{
	return (words[rand() % NUMWORDS]);
}


//
// Tell the user which characters in the guessed word are 
// correct.
//
// Input:
//		guessedWord - The word that the user has guessed
//		correctWord - The correct answer, generated by the program
//
// Output:
//		The user gets the word spelled back out with the 
//		characters guessed correctly filled in.
//
void userFeedback(char *guessedWord, char *correctWord)
{
	if (strlen(guessedWord) != strlen(correctWord))
	{
		cout << "Your word wasn't " << strlen(correctWord) << " characters long!" << endl << flush;
	}
	else
	{
		int charNum;	// Yes, you can declare variables here
		cout << "Correct letters: ";
		for (charNum=0; charNum < strlen(guessedWord); charNum++)
		{
			if (guessedWord[charNum] == correctWord[charNum])
			{
				cout << guessedWord[charNum];
			}
			else
			{
				cout << '-';
			}
		}
		cout << endl << flush;
	}
}


//
// Play a single game of guess the word.  Choose the random word,
// tell the user how long it is, and loop until the user gets
// it right.
//
void playOneGame()
{
	char* correctWord = chooseWord();	// Get a new random word
	char guessedWord[MAXWORDL
	cout << endl << "I have chosen a word " << strlen(correctWord) << " characters long" <<endl;

	// do-while loop used here since this logic always repeats
	// at least once.
	do 
	{
		cout << "What is your guess? " << flush;

		// No error checking.  If the user typed in a word
		// longer than MAXWORDLENGTH we might be in trouble.
		cin >> guessedWord;

		// If word is not correct, give the user hints.
		if (strcmp(guessedWord, correctWord))
		{
			userFeedback(guessedWord, correctWord);
		}
	} 
	while (strcmp(guessedWord, correctWord));
		
	cout << "Congratulations, you've guessed the word!";
	cout << endl << endl << flush;
}



// 
// Ask the user if they want to play another game. The user must
// return a 'y' to play again.  Any other response is interpreted
// as a "no".
//
int playAgain()
{
	char answer;

	cout << "Would you like to play again ('y' for yes)? " << flush;
	cin >> answer;
	return (answer == 'y');
}


//
// Keep playing the guess a word game until the user decides
// that enough is enough
//
// Note: a do-while loop is used here because the game is
// always played once.  
//
void playGames()
{
	do
	{
		playOneGame();
	} 
	while (playAgain());
}



//
// The main program.  Does all initializations (right now that
// only includes the random-number generator), gives the user
// instructions, and then plays games.
//
// Note:  this function is very mini// an outline of the program and should do very little "real"
// work.
//
void main()
{
	// Seed the random number generator.  In the VC++
	// world the preferred way to do this seems to be
	// to send the number returned by the time() function.
	// time() returns the number of seconds elapsed since
	// 01/01/1970.  It stores the value in a pointer you can
	// send to it, but if you send it a NULL, which we did here,
	// then it does not try to store the value.  srand() expects
	// an unsigned int, so we must convert the signed int returned 
	// by time() into an unsigned int.  This is a safe conversion,
	// since the value returned by time() will always be a positive
	// number in the legal range of an unsigned int.
	srand(unsigned(time(NULL)));

	// Tell the user how to play
	userInstructions();

	// Play games until the user wants to quit
	playGames();

	// Thank you, and good night.
	cout << "Thank you for playing!!" << endl;
}