Question

我刚开始学习C ++。我目前正在使用Bloodshed Dev C ++。我正在创建一个非常基本和简单的岩纸和剪刀游戏。除了退出循环之外，程序中的所有内容都正常工作。这是我的代码：

    /* 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（）;只是在那里让程序一旦完成运行就立即退出。

如果我破坏其他所有内容并且只留下do while和影响它的代码，这就是我所拥有的。

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

} while (keep_going = 'y');

如果我特意输入字母'y'，它应该只继续并再次开始循环但是无论我输入它只是似乎不能正常工作。提前感谢您提供的任何帮助。

Answer 1

您应该使用==（比较）而不是=（作业）：

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

} while (keep_going == 'y');

原因是，在分配变量时，会返回一个计算结果为true的值。例如：

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

Answer 2

比较时，请使用==代替=。 =使左侧值等于右侧，而==则用于比较两个对象。

正确代码：

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

} while (keep_going == 'y');

Answer 3

除了使用==之外，您还应该使用cin.get()，这样用户无需按Enter键：

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

Answer 4

//您正在寻找的语法是：

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

C ++不会在循环时退出

4 个答案: