在定义字符数组的 for 循环内应用输入限制（井字游戏）

Question

这是我的初始代码 - 用户可以使用它来玩井字游戏，方法是指定他们想要在 char 数组中添加零或交叉的位置 -

#include <stdio.h>
#include <iostream>
using namespace std;

int main()
{
   char a[3][3] = {{'1', '2', '3'}, {'4', '5', '6'}, {'7', '8', '9'}};
   cout << (char)a[0][0] << "    " << (char)a[0][1] << "    " << (char)a[0][2] << endl << endl << endl;
   cout << (char)a[1][0] << "    " << (char)a[1][1] << "    " << (char)a[1][2] << endl << endl << endl;
   cout << (char)a[2][0] << "    " << (char)a[2][1] << "    " << (char)a[2][2] << endl << endl << endl;

   int x, y;

   for (int i = 0; i < 5; i ++)
   {
       cout << "Input x: ";
       cin >> x;
       cout << "Input y: ";
       cin >> y;

       system("clear");

       a[x-1][y-1] =  'X';

       cout << (char)a[0][0] << "    " << (char)a[0][1] << "    " << (char)a[0][2] << endl << endl << endl;
       cout << (char)a[1][0] << "    " << (char)a[1][1] << "    " << (char)a[1][2] << endl << endl << endl;
       cout << (char)a[2][0] << "    " << (char)a[2][1] << "    " << (char)a[2][2] << endl << endl << endl;

       cout << "Input x: ";
       cin >> x;
       cout << "Input y: ";
       cin >> y;

       system("clear");

       a[x-1][y-1] =  'O';

       cout << (char)a[0][0] << "    " << (char)a[0][1] << "    " << (char)a[0][2] << endl << endl << endl;
       cout << (char)a[1][0] << "    " << (char)a[1][1] << "    " << (char)a[1][2] << endl << endl << endl;
       cout << (char)a[2][0] << "    " << (char)a[2][1] << "    " << (char)a[2][2] << endl << endl << endl;
   }
}

为了避免用户输入[1,3]之外的数组索引，我尝试实现一个if条件

if(x <= 0 && x > 3)
{
    cout << "Wrong! Enter again. Input x: ";
    cin >> x;
}

它不工作。由于 for 循环对 X 和 O 各迭代 5 次，因此输出要么卡在“输入 X”阶段，要么在 5 个“输入 X”后退出。

这是我尝试过的——最终接受了 5 个 X 输入，然后就退出了——

#include <stdio.h>
#include <iostream>
using namespace std;

int main()
{
   char a[3][3] = {{'1', '2', '3'}, {'4', '5', '6'}, {'7', '8', '9'}};
   cout << (char)a[0][0] << "    " << (char)a[0][1] << "    " << (char)a[0][2] << endl << endl << endl;
   cout << (char)a[1][0] << "    " << (char)a[1][1] << "    " << (char)a[1][2] << endl << endl << endl;
   cout << (char)a[2][0] << "    " << (char)a[2][1] << "    " << (char)a[2][2] << endl << endl << endl;

   int x, y;

   for (int i = 0; i < 5; i ++)
   {
       cout << "Input x: ";
       cin >> x;
       if(x <= 0 && x > 3)
       {
           cout << "Wrong! Enter again. Input x: ";
           cin >> x;
           continue;
       }
       else
       {
           continue;
       }

       cout << "Input y: ";
       cin >> y;
       if(y <= 0 && y > 3)
       {
           cout << "Wrong! Enter again. Input y: ";
           cin >> y;
           continue;
       }
       else
       {
           continue;
       }


       /*
       if(x <= 0 && x > 3)
       {
           cout << "Wrong! Enter again. Input x: ";
           cin >> x;
       }

       if(y <= 0 && y > 3)
       {
           cout << "Wrong! Enter again. Input y: ";
           cin >> y;
       }
       */

       system("clear");

       a[x-1][y-1] =  'X';

       cout << (char)a[0][0] << "    " << (char)a[0][1] << "    " << (char)a[0][2] << endl << endl << endl;
       cout << (char)a[1][0] << "    " << (char)a[1][1] << "    " << (char)a[1][2] << endl << endl << endl;
       cout << (char)a[2][0] << "    " << (char)a[2][1] << "    " << (char)a[2][2] << endl << endl << endl;

       cout << "Input x: ";
       cin >> x;
       if(x <= 0 && x > 3)
       {
           cout << "Wrong! Enter again. Input x: ";
           cin >> x;
           continue;
       }
       else
       {
           continue;
       }


       cout << "Input y: ";
       cin >> y;
       if(y <= 0 && y > 3)
       {
           cout << "Wrong! Enter again. Input y: ";
           cin >> y;
           continue;
       }
       else
       {
           continue;
       }


       /*
       if(x <= 0 && x > 3)
       {
           cout << "Wrong! Enter again. Input x: ";
           cin >> x;
       }

       if(y <= 0 && y > 3)
       {
           cout << "Wrong! Enter again. Input y: ";
           cin >> y;
       }
       */
       system("clear");

       a[x-1][y-1] =  'O';

       cout << (char)a[0][0] << "    " << (char)a[0][1] << "    " << (char)a[0][2] << endl << endl << endl;
       cout << (char)a[1][0] << "    " << (char)a[1][1] << "    " << (char)a[1][2] << endl << endl << endl;
       cout << (char)a[2][0] << "    " << (char)a[2][1] << "    " << (char)a[2][2] << endl << endl << endl;
   }
}

为什么我不能只在输入后有一个 if 语句，其中它检查它是否超出范围，如果是，它可以再次询问用户，然后继续？ - 这是我想要实现的。

Answer 1

我认为正确的运算符是 ||而不是 &&。

通过使用 &&，您建议必须同时发生 x3 才能采用 IF 语句！

尝试用英语大声朗读你的陈述会有所帮助，有助于你更好地理解它:)

Answer 2

为什么不能只在输入后有一个if语句，检查是否越界，如果是，可以再次询问用户，然后继续？

if 语句检查用户输入的有效性，但在输入有效之前它不会迭代。您需要有一个loop，它会一直运行到用户输入有效为止。

如下所示，

#include <iostream>

bool isGameCompleat(char a[3][3])
{
   /*check for all combination for the board for game complete*/
    if ((a[0][0] == a[0][1] && a[0][0] == a[0][2]) ||
        (a[1][0] == a[1][1] && a[1][0] == a[1][2]) ||
        (a[2][0] == a[2][1] && a[2][0] == a[2][2]) ||
        (a[0][0] == a[1][0] && a[0][0] == a[2][0]) ||
        (a[0][1] == a[1][1] && a[0][1] == a[2][1]) ||
        (a[0][3] == a[1][3] && a[0][3] == a[2][3]) ||
        (a[0][0] == a[1][1] && a[0][0] == a[2][2]) ||
        (a[0][3] == a[1][1] && a[0][3] == a[2][0]))
        return true;
    return false;
}

void printBoard(char a[3][3])
{
    std::cout << (char)a[0][0] << "    " << (char)a[0][1] << "    " << (char)a[0][2] << "\n\n\n";
    std::cout << (char)a[1][0] << "    " << (char)a[1][1] << "    " << (char)a[1][2] << "\n\n\n";
    std::cout << (char)a[2][0] << "    " << (char)a[2][1] << "    " << (char)a[2][2] << "\n\n\n";
}

int main()
{
    char a[3][3] = { {'1', '2', '3'}, {'4', '5', '6'}, {'7', '8', '9'} };

    int x, y;

    printBoard(a);

    for (int i = 0; (i < 9); i++)
    {
        int p;
        if ((i & 1) == 0) {
            std::cout << "X Turn ";
        }
        else {
            std::cout << "O Turn ";
        }

        std::cout << "Enter the position ";
        std::cin >> p;  

        /*derived  row and column from 0 to 9 position*/
        x = (p / 3);
        y = (p%3) -1;

        /*Validity check for input if wrong request for new input
         * out of range check and non-repeated tile is selected
         */
        while (p < 0 || p > 9 || (a[x][y] =='X') || (a[x][y]=='O'))
        {   
            std::cout << "Wrong! Enter again: ";
            std::cin >> p;
            x = (p / 3);
            y = (p%3) -1;
        }

        if ((i & 1) == 0) {
            a[x][y] = 'X';
        }
        else {
            a[x][y] = 'O';
        }

        system("clear");
        printBoard(a);

        if (isGameCompleat(a))
        {
            std::cout <<(  (i & 1) ? "O" : "X") << " wins";
            break;
        }
        else if (i == 8)
        {
            std::cout << "Game is draw";
        }           
    }
}