Как подождать допустимый ввод

Question

Я переучиваю битву, и она основана на монете, головах или хвостах. У меня есть пользовательский ввод «H, h, T, t», чтобы определить битву. Моя проблема заключается в том, что я реализовал то, что они могут быть только допустимыми входами, но если я вхожу в «G», например, он отображает неверный ввод, но все же выполняется. Как я могу заставить свою программу ждать одного из этих допустимых значений? Благодаря!

#include <iostream> 
#include <iomanip> 
#include <cstdlib> 
#include <ctime> 
#include <sstream> 

using namespace std; 

int main() 

{ 
    //A little information about the battle 

    cout << "\t\t\tLet the\n\n"; 
    cout << "Decision of heads or tails on the coin react history\n"; 

    cout << "\t\t/---------------------\\" << endl; 
    cout << "\t\t| RETURN TO SEVEN DAYS|\n"; 
    cout << "\t\t\\---------------------/\n\n" << endl; 

    //Main Battle 

    cout << "It is July 1, 1862, the final day\n"; 
    cout << "of the Battle of Seven Days...\n\n"; 

    cout << "In this re-enactment of the second day\n"; 
    cout << "of battle, you are George B. McClellan\n"; 
    cout << "in charge of the Unionists\n\n"; 

    cout << "We will flip a coin to determine the\n"; 
    cout << "outcome of the small battles for\n"; 
    cout << "territories within the Seven Days area\n\n"; 

    cout << "You will have to predict whether the coin\n"; 
    cout << "will come up heads or tails...\n\n"; 

    cout << "In the actual Battle at Seven Days,\n"; 
    cout << "the Northern troops turned back Lee's\n"; 
    cout << "final assaults at Malvern Hill(July\n"; 
    cout << "1)....\n\n"; 

    cout << "The confederates lost about 16,000\n"; 
    cout << "men...\n\n"; 

    cout << "The Unionists lost about 20,000 men...\n\n"; 

    cout << "McClellan's failure to capture\n"; 
    cout << "Richmond, and the subsequent\n"; 
    cout << "withdrawal of the Union's Army from\n"; 
    cout << "the Yorktown Peninsula, signified the\n"; 
    cout << "end of the Peninsular Campaign\n\n"; 

    //Running through the battles 

    int battleName = 1; 

    for (; battleName <= 9; battleName += 1){ 

     cout << "Battle \t\n" << battleName << " - "; 

     switch (battleName) 
     { 
     case 1: cout << "Oak Grove "; 
      break; 
     case 2: cout << "Mechanicsville "; 
      break; 
     case 3: cout << "Gaines Mill "; 
      break; 
     case 4: cout << "Garnett Farm "; 
      break; 
     case 5: cout << "Golding Farm "; 
      break; 
     case 6: cout << "The Peach Orchard "; 
      break; 
     case 7: cout << "Savage Station "; 
      break; 
     case 8: cout << "Frayser Farm "; 
      break; 
     case 9: cout << "Malvern Hill "; 
      break; 
     } 

     //Asking the user for input 

     cout << "\nNow Now, General McClellan\n"; 
     cout << "What do you predict the coin outcome will be, \n"; 
     cout << "Heads (H) or Tails (T)? \n"; 
     cout << "Please choose either Heads or Tails:\n"; 

     string userInput; 

     cin >> userInput; 

     if (userInput == "H" || userInput == "h") 
      cout << "\n You have chosen heads!" << endl; 

     if (userInput == "T" || userInput == "t") 
      cout << "\n You have chosen tails!" << endl; 

     else if (!(userInput == "H" || userInput == "h" || userInput == "T" || userInput == "t")) 
      userInput = 'H'; 
      cout << "Invalid input. You must choose either heads or tails!\n"; 

     cout << "\t\tPlease get ready to fight, General McClellan!!\n\n\n"; 


     //random number function 

    unsigned seed = time(0); 
    srand (seed); 

    //to integers, heads or tails 

    const int MIN_VALUE = 0; 
    const int MAX_VALUE = 1; 
    int coin = 0; 

     coin = (rand() % (MAX_VALUE - MIN_VALUE +1)) + MIN_VALUE; 

    //Deciding the actual coin flip 

    cout << "The result of the coin flip was "; 

     if (coin == 0) 
      cout << "heads!\n\n\n"; 

     if (coin == 1) 
      cout << "tails!\n\n\n"; 


    //incrementing values of the winner 

    int computerScore = 0; 
    int score = 0; 



    if(((userInput == "T" || userInput == "t") && coin == 1)) 
    { 
     cout << "Well done, General \nMcClellan...\n You have defeated Lee!\n"; 
     score += 1; 
    } 

    else if(((userInput == "H" || userInput == "h") && coin == 0)) 
    { 
     cout << "Well done, General \nMcClellan...\n You have defeated Lee!\n"; 
     score += 1; 
    } 

    else 
    { 
     cout << "I am sorry, General\nMcClellan...\n But the battle goes to Lee!"; 
      computerScore += 1; 

    } 

     cout << "\n So far: McClellan " << score << " victories,\n" << "Lee " << computerScore << "\n\n\n"; 



    //Scoring 

    if (score > computerScore) 
      cout << "The results show that\n George B. McClellan\nwon the majority of the battles\nand is thus declared the victor\non July 1 1862.\n\n\n"; 

    if (score < computerScore) 
     cout << "The results show that\nRobert E Lee\nwon the majority of the battles\nand is thus declared the victor\non July 1 1862\n\n\n"; 

    } 

    return 0; 
} 

Answer 1

здесь самый простой способ, я использовал бы char как вход. EDIT: char не будет работать в этом случае, это одна из тех вещей, которые я забыл при кодировании в C++.

string userINput; 
while ((cin >> userInput) != "H" && userInput != "h" && 
      userInput != "T" && userInput != "t"); 

, то я бы избавиться от этого кода:

else if (!(userInput == "H" || userInput == "h" || userInput == "T" || userInput == "t")) 
      userInput = 'H'; 
      cout << "Invalid input. You must choose either heads or tails!\n"; 

все вместе.

Вы также проблема здесь вы хотите выполнить UserInput = H и печатающую сообщение после того, как другой, но вы не имеете {}, так что должно быть так, чтобы работать:

else if (!(userInput == "H" || userInput == "h" || userInput == "T" || userInput == "t")) { 
      userInput = 'H'; 
      cout << "Invalid input. You must choose either heads or tails!\n"; 
    }