C++ Hangman Game, how to make "right" letter stick - c++

Question

I am trying to do a hangman project, but my code isn't working. Whenever I put in the proper letter, the code tells me it is wrong (even though it is right). Not really sure why - the code worked at some point but I changed some things and now I don't know why it doesn't work. So it is probably a simple fix, but I am just not seeing it.
Any help would be very appreciated!
#include <iostream>
using namespace std;
int letterFill (char, string, string&);
int main()
{
string name;
int maxAttempts = 5;
int wrongGuesses;
char letter;
srand(time(0));
const string wordList[15] = { "hanukkah", "sparklers", "mistletoe", "menorah", "presents", "reindeer",
"kwanzaa", "snowman", "eggnog", "celebration", "yuletide", "resolution", "nutcracker", "ornaments", "gingerbread" };
string correctWord = wordList[rand() % 15];
string unknown(correctWord.length(),'*');
cout << correctWord << endl;
cout << "Welcome to a fun game of winter holiday hangman! What is your name? " << endl;
cin >> name;
cout << name <<", there are some simple things you should know about this game before you start playing!" << endl;
cout << "You will be trying to guess a randomly selected word by typing in ONE letter at a time " << endl;
cout << "You will have " << maxAttempts << " tries before losing the game " << endl;
cout << "And remember, all of the words are winter holiday related. Good luck " << name <<"!" << endl;
cout << "*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*" <<endl;
while (wrongGuesses == 0)
{
cout << "Guess a letter" << cout;
cin >> letter;
if (letterFill(letter, correctWord, unknown)==0)
{
cout << endl << "That letter is not in this word! Try again " << endl;
wrongGuesses = wrongGuesses + 1;
}
else
{
cout << endl << "You found a letter! Keep up the good work! " << endl;
}
if (correctWord==unknown)
{
cout << correctWord << endl;
cout << "Congratulations! You guessed the correct word!" << endl;
}
}
while (wrongGuesses == 1)
{
cout << "You have 4 guesses left " << endl;
cout << "Guess a letter " << cout;
cin >> letter;
if (letterFill(letter, correctWord, unknown)==0)
{
cout << endl << "That letter is not in this word! Try again " << endl;
wrongGuesses = wrongGuesses + 1;
}
else
{
cout << endl << "You found a letter! Keep up the good work! " << endl;
}
if (correctWord==unknown)
{
cout << correctWord << endl;
cout << "Congratulations! You guessed the correct word!" << endl;
}
}
while (wrongGuesses == 2)
{
cout << "You have 3 guesses left " << endl;
cout << "Guess a letter " << cout;
cin >> letter;
if (letterFill(letter, correctWord, unknown)==0)
{
cout << endl << "That letter is not in this word! Try again " << endl;
wrongGuesses = wrongGuesses + 1;
}
else
{
cout << endl << "You found a letter! Keep up the good work! " << endl;
}
if (correctWord==unknown)
{
cout << correctWord << endl;
cout << "Congratulations! You guessed the correct word!" << endl;
}
}
while (wrongGuesses == 3)
{
cout << "You have 2 guesses left " << endl;
cout << "Guess a letter " << cout;
cin >> letter;
if (letterFill(letter, correctWord, unknown)==0)
{
cout << endl << "That letter is not in this word! Try again " << endl;
wrongGuesses = wrongGuesses + 1;
}
else
{
cout << endl << "You found a letter! Keep up the good work! " << endl;
}
if (correctWord==unknown)
{
cout << correctWord << endl;
cout << "Congratulations! You guessed the correct word!" << endl;
}
}
while (wrongGuesses == 4)
{
cout << "You have 1 guess left " << endl;
cout << "Guess a letter " << cout;
cin >> letter;
if (letterFill(letter, correctWord, unknown)==0)
{
cout << endl << "That letter is not in this word! Try again " << endl;
wrongGuesses = wrongGuesses + 1;
}
else
{
cout << endl << "You found a letter! Keep up the good work! " << endl;
}
if (correctWord==unknown)
{
cout << correctWord << endl;
cout << "Congratulations! You guessed the correct word!" << endl;
}
}
while (wrongGuesses == 5)
{
cout << "Sorry " << name << " you have made 5 wrong guesses!" << endl;
cout << "Game over. Click any key to exit. Play again soon :) " << endl;
if (letterFill(letter, correctWord, unknown)==0)
{
cout << endl << "That letter is not in this word! Try again " << endl;
wrongGuesses = wrongGuesses + 1;
}
else
{
cout << endl << "You found a letter! Keep up the good work! " << endl;
}
if (correctWord==unknown)
{
cout << correctWord << endl;
cout << "Congratulations! You guessed the correct word!" << endl;
}
}
system("pause");
return 0;
}
int letterFill (char guessLetter, string mysteryWord, string& guessWord)
{
int x;
int matches=0;
int lengthWord=mysteryWord.length();
for (x = 0; x< lengthWord; x++)
{
if (guessLetter == mysteryWord[x])
return 0;
if (guessLetter == mysteryWord[x])
{
guessWord[x] = guessLetter;
matches++;
}
}
return matches;
}

Answer 1

You aren't updating the string guessWord in your int letterFill() function. As soon as you see a letter that matches you return without entering that second if statement.
I assume what you want is only to return after fully updating the guessWord, based on that what you want to do is iterate through the string, updating guessWord as you find matches and after your loop do a check
if(matches == 0) return 0;
else return matches;