Having trouble incorporating a function into my main function

[kevmeister77]

Hi guys! Long time listener, first time caller here. I'm doing a hangman program, and I know exactly where I'm stuck - I had to build a function that tested a guess to see if it was alphabetic, or previously used, but try as I might, my getNewGuess(string prevGuesses) function isn't working at all. It looks like I just never go into the loop. If I comment out the function and just use

cin >> guess;

it works fine, and keeps track of prevGuesses.

Here's what I'm working with:

#include <iostream>
#include <iomanip>
#include <string>
#include "assn.h"
using namespace std;

int main()
{  
    int wrongGuess = 0;
    int guessesLeft = 7 - wrongGuess;
    string phrase, prevGuesses;
    char guess, validGuess;
    
    
    cout << "Enter phrase: ";
    getline(cin, phrase);
    
    
    
    clearScreen();
     
    string unsolved = setupUnsolvedPhrase(phrase);
    cout << "Phrase : " << unsolved << endl;
    cout << "Enter a guess: ";
    cin >> guess;
    unsolved = updateUnsolvedPhrase(phrase, unsolved, guess);
    cout << endl;
    
    while (phrase!=unsolved)
    { 
          
         cout << "Phrase : " << unsolved << endl << endl;
         cout << "Guessed so far: " << prevGuesses << endl;
         cout << "Wrong guesses left: " << guessesLeft << endl << endl;
         cout << "Enter a guess: ";
         cin >> guess;
         //getNewGuess(prevGuesses);
         prevGuesses += guess;
         cout << "Previous guesses: " << prevGuesses << endl;
         unsolved = updateUnsolvedPhrase(phrase, unsolved, guess);           
    }
    cout << "Congratulations!!" << endl;
    
    
}

My getNewGuess function looks like this, essentially:

/**
@brief Gets valid guess as input.
A guess is taken as input as a character. It is valid if
1) it is an alphabetic character and
2) the character has not already been guessed
@param prevGuesses the string containing all characters guessed so far
@return a valid guess and only a valid guess as a character
*/
char getNewGuess(string prevGuesses)
{
	char guess;
	cin >> guess;
	prevGuesses += guess;
        
        while (isalpha(guess))
        {
	  for (int i = 0; i< prevGuesses.length(); i++)
	  {
		if (prevGuesses.at(i) != guess)
		{
			return (guess);
		}
		else
		{
			wrongGuess++;
		}	
	  }
       }
}

It's weird because I built two other functions and am using them fine, so I don't see what's going on with this one! I feel like I'm having trouble with the scope of the function, like the instructor talked about in class, but, again, I feel like I'm not returning anything I shouldn't be... Any thoughts? Oh, when I run the program with the function, prevGuesses isn't kept track of properly, and regardless of the next guess I input, it doesn't update my unsolved string, but as soon as I take it out it works properly. I HAVE to have a function that keeps track of prevGuesses and returns guess while isalpha(guess) is true though.

If I'm missing anything, I apologize. I've searched and didn't find anything similar. Any help is greatly appreciated!!

[tfityo]

Modify char getNewGuess(string prevGuesses) to char getNewGuess(string& prevGuesses). It allows you to modify the argument.

In you version you modify copy of the argument.

Read more here: http://www.learncpp.com/cpp-tutorial/73-passing-arguments-by-reference/

[kevmeister77]

Thanks for the suggestion, I appreciate it. However, we were told specifically to build the functions with given parameters, and other students were told that if they passed it with reference they'd get points dinged -- any ideas on how to do it without that? I apologize, I should've mentioned that earlier. Worst case scenario, I will do that and take the points lost. Better to get correct output at least.


It's really annoying though - It's like, how can I keep track of prevGuesses when it being in a function causes it to lose it's value after the funciton is called? Auugghh!!! Putting it outside the function just causes it to not keep track of guesses called within the function.

Did the getNewGuess function look like it was built ok?

[cire]

You are only getting 1 guess in getNewGuess. If it is alphabetic but invalid, you loop endlessly instead of getting a new "valid" guess. If it is not alphabetic you return nothing which means your return value is junk -- no doubt your compiler warns you of this.

[inurockx]

You aren''t passing the prevGuesses though, what you need to pass is the guess. And you can update your your prevGuesses in your main function.

[kevmeister77]

cire - fortunately or unfortunately as it may be, I got no compiler warnings that I could see. I did take your advice into consideration, it was very useful so thank you for that. Same with you, inurockx.