在do-while循环中输入验证出现C ++错误

我正在为一个学校项目创建一个非常简单的猜数字游戏，但在重复主菜单时遇到了麻烦。我使用 do-while循环创建了它，而我遇到的问题是菜单选择变量是 int ，所以当我（或用户）输入从菜单中选择} while（condition）时，意外地输入了 non-int ，无法捕获它并且程序无限重复。相反，如果在菜单选择中输入无效int ，程序将捕获该消息，显示无效输入消息，然后重复主菜单。

I'm creating a very simple number guessing game for a school project and am having trouble with the repeating main menu. I created it using a do-while loop and the problem I'm having is that the menu selection variable is an int, and so when I (or the user) enters a non-int input by accident when selecting from the menu the }while(condition) at the end of the main loop can't catch it and the program repeats infinitely. Conversely if you enter an invalid int at menu selection the program catches it displays the "invalid input" message and then repeats the main menu.

很难以书面形式确切解释我的意思，因此这里是带有相关星号的相关行的源代码。我将另存为.cpp，并使用 g ++ -ansi -pedantic -Wall -Werror 在Linux中进行编译。老师禁止在条件语句中进行硬编码，因此禁止使用全局常量。

It's kind of hard to explain in writing exactly what I mean so here is the source code with relevant lines denoted with an asterisk. I'm saving as .cpp and am compiling in linux using g++ -ansi -pedantic -Wall -Werror The teacher has forbidden hardcoding in conditional statements hence the global constants.

#include <iostream>
#include <ctime>
#include <cstdlib>
using namespace std;
const int PLAY = 1, HIGH_SCORE = 2, EXIT = 3;
const char YES = 'y', NO = 'n';

int main()
{
// Randomly generated value
  int randomNumber;
// User input
  int userGuess, menuChoice;
  char repeat;
// Calculated value
  int numberOfGuesses;
// Place-holder values (to be replaced by calculated values)
  int score1 = 1000, score2 = 2000, score3 = 3000;

  cout << endl << endl;
  cout << "Greetings! This is a number guessing game where I think of" << endl
       << "a whole number between one and ten and you try to guess it!" << endl
       << "You can guess as many times as you like, so don't be afraid" << endl
       << "to use trial and error, but your score is based on the " << endl
       << "number of guesses you make (the lower the better) so don't " << endl
       << "guess too haphazardly. Remember, only guess whole numbers!" << endl
       << endl;

  do
  {
    cout << endl << "Main menu." << endl
         << "1. Play game" << endl
         << "2. Display high scores" << endl
         << "3. Exit game" << endl
         << "Please select an option: ";
    cin >> menuChoice;

    if (cin.fail()){     
      cout << "Please enter a valid choice" << endl;
      continue;
    } 
    cin.ignore();

    switch(menuChoice)
    {
      case PLAY:
      do
      {
        unsigned seed = time(0);
        srand(seed);
        randomNumber = 1 + rand() % 10;

        cout << endl << "Press enter when you're ready to begin!";
        cin.ignore();
        cout << "Ok I thought of one!" << endl << endl;

        numberOfGuesses = 0;

        do
        {
          numberOfGuesses++;

          cout << "Enter your guess: ";
          cin >> userGuess;
          cin.ignore();

// Check user's guess
          if (userGuess == randomNumber)
            cout << "Correct! That was impressive!" << endl << endl;
          else if (userGuess < randomNumber)
            cout << "Not quite, you guessed low." << endl << endl;
          else if (userGuess > randomNumber)
            cout << "Not quite, you guessed high." << endl << endl;
        }while (userGuess != randomNumber);

        cout << "Your score for this game was " << numberOfGuesses << endl;

// Determine if a high score was beaten
        if (numberOfGuesses <= score1)
        {
          score3 = score2;
          score2 = score1;
          score1 = numberOfGuesses;
          cout << "That's a new all time high score!" << endl;
        }
        else if (numberOfGuesses <= score2)
        {
          score3 = score2;
          score2 = numberOfGuesses;
          cout << "That's a new high score!" << endl;
        }
        else if (numberOfGuesses <= score3)
        {
          score3 = numberOfGuesses;
          cout << "That's a new high score!" << endl;
        }
        else
        {
          cout << endl; 
        }

        cout << "Would you like to play again? y/n: ";
        cin.get(repeat);
        cin.ignore();

        while (tolower(repeat) != YES && tolower(repeat) != NO)
        {
          cout << endl;
          cout << "Sorry, that is an invalid choice." << endl
               << "Please enter 'y' for yes or 'n' for no: ";
          cin.get(repeat);
          cin.ignore();
        }
      }while (tolower(repeat) == YES); 
        break;

      case HIGH_SCORE:
      cout << endl << "High Score 1: " << score1 << endl
           << "High Score 2: " << score2 << endl
           << "High Score 3: " << score3 << endl << endl;
      cout << "Press enter to continue. ";
      cin.ignore();
        break;

      case EXIT: 
      cout << endl << "Thanks for playing, I'll see you next time!" << endl << endl;
        break;

      default:
      cout << endl << "That is an invalid selection, please enter '1', '2' or '3'"
           << endl;
        break;
    } 
  }while (menuChoice != EXIT);

  return 0;
}

针对当前答案进行了代码编辑。

Code Edited in regards to current answer.

如果需要更多信息，请让我知道，谢谢您！

Please let me know if you need anymore information, thanks in advanced!