C++不會退出while while循環

Question

我剛開始學習C++。我目前使用Bloodshed Dev C++。我是在創建一個非常簡單和簡單的岩石紙和剪刀遊戲。除了退出循環外，程序中的所有內容都正常工作。這裏是我的代碼：

/* FILE INFO 

File Name: Chapter 3 - Project 1.cpp 
Author: Richard P. 
P#: --------- 
Assignment: Chapter 3 Project 1 

*/ 

#include <iostream> 
using namespace std; 
int main() 
{ 

char Player1_choice; 
char Player2_choice; 

char keep_going; 

cout << "Welcome to Rock, Paper, Scissors! The rules of the game are simple:\n\n" 
    << "Enter either the letter P (for Paper), S (for Scissors), or R (for Rock)\n\n" 
    << "Paper covers rock, Rock breaks scissors, Scissors cut paper\n\n" 
    << "If both players pick the same choice then it is a draw!\n" 
    << "-----------------------------------------------------------------------------\n\n"; 

do 
{ 
    cout << "Okay, player 1, what is your choice? Is it R(rock), P(paper), or S(scissors)?\n"; 
    cin >> Player1_choice; 

    switch (Player1_choice) //I COULD DO A NESTED SWITCH STATMENT BUT FOR VARIETY I AM USING SWITCH AND IF STATMENTS. 
    { 
      case 'R': 
      case 'r': 

       cout << "\n\nOkay, player 2, what is your choice? Is it R(rock), P(paper), or S(scissors)?\n"; 
       cin >> Player2_choice; 

       if (Player2_choice == 'R' || Player2_choice == 'r') 
         cout << "It's a draw!\n"; 
       else if (Player2_choice == 'P' || Player2_choice == 'p') 
         cout << "Sorry Player 1, you lose!\n\n THE WINNER IS PLAYER 2"; 
       else if (Player2_choice == 'S' || Player2_choice == 's') 
         cout << "Sorry Player 2, you lose!\n\n THE WINNER IS PLAYER 1"; 
       else 
         cout << "That is not a valid entry! Please read the rules and play again :)\n"; 


       break; 

      case 'P': 
      case 'p': 

       cout << "\n\nOkay, player 2, what is your choice? Is it R(rock), P(paper), or S(scissors)?\n"; 
       cin >> Player2_choice; 

       if (Player2_choice == 'R' || Player2_choice == 'r') 
         cout << "Sorry Player 2, you lose!\n\n THE WINNER IS PLAYER 1"; 
       else if (Player2_choice == 'P' || Player2_choice == 'p') 
         cout << "It's a draw!\n"; 
       else if (Player2_choice == 'S' || Player2_choice == 's') 
         cout << "Sorry Player 1, you lose!\n\n THE WINNER IS PLAYER 2"; 
       else 
         cout << "That is not a valid entry! Please read the rules and play again :)\n"; 

       break; 

      case 'S': 
      case 's': 

       cout << "\n\nOkay, player 2, what is your choice? Is it R(rock), P(paper), or S(scissors)?\n"; 
       cin >> Player2_choice; 

       if (Player2_choice == 'R' || Player2_choice == 'r') 
         cout << "Sorry Player 1, you lose!\n\n THE WINNER IS PLAYER 2"; 
       else if (Player2_choice == 'P' || Player2_choice == 'p') 
         cout << "Sorry Player 2, you lose!\n\n THE WINNER IS PLAYER 1"; 
       else if (Player2_choice == 'S' || Player2_choice == 's') 
         cout << "It's a draw!\n"; 
       else 
         cout << "That is not a valid entry! Please read the rules and play again :)\n"; 

       break; 

      default: 
        cout << "That is not a possible entry.\n";   
    } 

    cout << "\n\nKeep playing?\n"; 
    cin >> keep_going; 

} while (keep_going = 'y'); 

    cout << "You have chosen not to keep playing. Press Enter to exit the game"; 
cin.get(); 
cin.get(); 
return 0; 
} 

cin.get（）;只是爲了防止程序一旦完成運行就立即退出。

如果我把其他所有東西都放下來，只留下那些影響它的代碼，這裏是我的。

char keep_going; 
do 
{  
     cout << "\n\nKeep playing?\n"; 
     cin >> keep_going; 

} while (keep_going = 'y'); 

它應該只能繼續並再次啓動循環，如果我特別輸入字母'y'但無論我輸入它只是似乎不能正常工作。預先感謝任何和所有幫助。

Answer 1

您應該使用==（比較），而不是=（分配）：

do 
{  
     cout << "\n\nKeep playing?\n"; 
     cin >> keep_going; 

} while (keep_going == 'y'); 

原因是，是，當你分配一個變量，計算結果爲true返回一個值。例如：比較東西的時候

char keep_going; 
do {  
    cout << "\n\nKeep playing?\n"; 
    keep_going = cin.get(); 
} while (keep_going == 'y'); 

Answer 2

除了使用==，你應該使用cin.get()所以用戶不需要按Enter鍵。 =使左側值等於右側，而==用於比較兩個對象。

正確的代碼：

do 
{  
    cout << "\n\nKeep playing?\n"; 
    cin >> keep_going; 

} while (keep_going == 'y'); 

Answer 3

使用==，而不是=：

if(foo = 42) { //equivalent to if(true) {...} 
    cout << "This is evaluating variable assignment"; 
} else { 
    cout << "This line will never be reached"; 
} 

Answer 4

//語法你要找的是這樣的：

char keep_going; 
do { 
//some statements 
} while(cin.get(keep_going));