getline() function reading in whitespace before input is entered - c++

Question

Alright, I wrote a game of hangman. The game works great, except after the user finishes the game, and enters the char value of Y to play again.
I have traced the problem down to the getline() function at the start of my do-while loop. If I enter Y, then the do-while loop succesfully repeats, but the getline function seems to already think that there is input in cin, even though I don't enter anything.
Here is my code so far:
#include<iostream>
#include<string>
using namespace std;
int main() {
string secretWord;
string secretWordClean = "";
string guessedLetters; //to be loaded with _ characters equal to length of secretWord
string incorrectlyGuessedChars = "";
char individualCharGuess;
char playAgain;
size_t countOfLetters = 0; //begine count at 0
size_t guessesRemaining;
int guessedUsed;
begin_game://label which we can use to bring us back to the start of the do-while loop at any time
do{//start of the game
cout << "Please enter a secret word: ";
getline(cin, secretWord); //y getline is cuaing the issue
for(int i = 0; i < secretWord.length(); i++){
if (isalpha(secretWord[i])){
secretWordClean += secretWord[i];
}
}
secretWord = secretWordClean; //assign all alpha secret word string back to original variable for better readability
guessesRemaining = secretWord.length() * 2;
for(int i = 0; i < secretWord.length(); i++){
guessedLetters += "_"; //fills guessedLetters with blanks equal to the length of the secretWord
}
cout << "Please guess a letter, you have " << guessesRemaining << " guesses remaining!" << endl;
cin >> individualCharGuess;
for(int i = 0; i < secretWord.length(); i++){ //every complete iteration of this for loop = one single guess
if(secretWord[i] == individualCharGuess){
guessedLetters[i] = individualCharGuess; //will replace the spaces with the correct character, if guessed
countOfLetters++; //if any letter is guessed correctly, this indicator will be inrimented above 0
continue;
}
if(secretWord.find(individualCharGuess) == string::npos){
if(incorrectlyGuessedChars.find(individualCharGuess) == string::npos){
incorrectlyGuessedChars += individualCharGuess;
}
}
}
if(secretWord.compare(guessedLetters) == 0){
cout << "You win! The word was: " << secretWord << endl;
guessedUsed = ((secretWord.length() * 2) - guessesRemaining) + 1 ;
cout << "You used " << guessedUsed << " guesses." << endl;
cout << "Play again? Enter Y for Yes, or anything else to exit: ";
cin >> playAgain;
if(playAgain != 'Y'){
break; //exit the loop if user guesses all the letters and doesn't want to play again
}
else {
goto begin_game;
}
}
guessesRemaining--; //we decriment our total guesses remaining if the user does not win the game or run out of guesses
if(countOfLetters > 0){
cout << "You have correctly guessed a letter!" << endl;
cout << "Here are the letters you have guessed correctly so far: ";
cout << guessedLetters << endl;
cout << "Here are the letters you have guessed incorrectly so far: ";
cout << incorrectlyGuessedChars << endl;
countOfLetters = 0; //reset the counter to prepare for next iteration of do-while loop
}
else if (guessesRemaining <= 0) {
cout << "You have run out of guesses!" << endl;
cout << "Here are the letters that you guessed correctly: ";
cout << guessedLetters << endl;
cout << "Here are the letters you guessed incorrectly: ";
cout << incorrectlyGuessedChars << endl;
cout << "The secret word was: " << secretWord << endl;
cout << "Play again? Enter Y for Yes, or anything else to exit: ";
cin >> playAgain;
if(playAgain != 'Y'){
break; //exit the loop if user guesses all the letters and doesn't want to play again
}
else goto begin_game;
}
else {
cout << "You guessed wrong! Keep trying, " << guessesRemaining << " guesses to go!" << endl;
cout << "Here are the letters you have guessed correctly so far: ";
cout << guessedLetters << endl;
cout << "Here are the letters you have guessed incorrectly so far: ";
cout << incorrectlyGuessedChars << endl;
}
}while (secretWord.compare(guessedLetters) != 0 || guessesRemaining != 0); //use to repeat the request for a single char guess
return 0;
}

Answer 1

You are mixing formatted and unformatted I/O: reading a character will stop immediately after reading the character. Since after entering the character you entered a newline the newline still sticks in the stream, read for getline() to terminate the line. You should skip leading whitespace before using std::getline(), e.g.:
if (std::getline(std::cin >> std::ws, s)) {
...
}
Alternatively, you could use ignore() to ignore all characters up to and including the newline. Note that ignoring just one character won't work reliably as a sequence of spaces between the '\n'. To use ignore() you should use the proper magic number instead:
std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
BTW, you should also always verify that input was actually successful as you'd otherwise easily get incorrect behavior when it isn't.

Answer 2

Don't mix token extraction using >> and line extraction using getline. The former doesn't remove newlines, so the next getline call after token extraction may end up reading the remaining bit of the previous line, which may be an empty string.
If you must mix the two kinds of input, use std::cin >> std::ws to gobble up stray whitespace (including the newline) before using getline.