c++ - Tic Tac Toe 游戏无法运行

Question

所以我大约一周前学习了编程。我决定制作一个井字游戏作为一个业余爱好项目，我启动并运行了一个基本的游戏输入法，但有一个方面不起作用。我做了一段非常简化的代码来验证是否有人在玩了 5 步之后就赢了。一旦有人赢了，它就应该显示“游戏结束!”但它不是出于某种原因。任何人都可以帮忙吗？_____________ 注意:代码中验证某人是否获胜的方法尚未完成。它仅适用于行，因为当我测试它时，它不起作用。

#include <iostream>
#include <cstdlib>

using namespace std;
int main()
{
    char grid[3][3];
    int p;
    cout << "Enter column number. \n";
    cin >> p;
    int o;
    cout << "Enter row number. \n";
    cin >> o;
    for (int y = 0; y < 3; y++)
    {
        for (int x = 0; x < 3; x++)
        {
            grid[x][y] = '-';
            grid[o][p] = 'X';
            cout << grid[x][y] << " ";
        }
        cout << endl;
    }
    int q;
    cout << "Enter column number. \n";
    cin >> q;
    int r;
    cout << "Enter row number. \n";
    cin >> r;
    for (int y = 0; y < 3; y++)
    {
        for (int x = 0; x < 3; x++)
        {
            grid[x][y] = '-';
            grid[o][p] = 'X';
            grid[r][q] = 'O';
            cout << grid[x][y] << " ";
        }
        cout << endl;
    }
    int s;
    cout << "Enter column number. \n";
    cin >> s;
    int t;
    cout << "Enter row number. \n";
    cin >> t;
    for (int y = 0; y < 3; y++)
    {
        for (int x = 0; x < 3; x++)
        {
            grid[x][y] = '-';
            grid[o][p] = 'X';
            grid[r][q] = 'O';
            grid[t][s] = 'X';
            cout << grid[x][y] << " ";
        }
        cout << endl;
    }
    int v;
    cout << "Enter column number. \n";
    cin >> v;
    int b;
    cout << "Enter row number. \n";
    cin >> b;
    for (int y = 0; y < 3; y++)
    {
        for (int x = 0; x < 3; x++)
        {
            grid[x][y] = '-';
            grid[o][p] = 'X';
            grid[r][q] = 'O';
            grid[t][s] = 'X';
            grid[b][v] = 'O';
            cout << grid[x][y] << " ";
        }
        cout << endl;
    }
    int f;
    cout << "Enter column number. \n";
    cin >> f;
    int g;
    cout << "Enter row number. \n";
    cin >> g;
    for (int y = 0; y < 3; y++)
    {
        for (int x = 0; x < 3; x++)
        {
            grid[x][y] = '-';
            grid[o][p] = 'X';
            grid[r][q] = 'O';
            grid[t][s] = 'X';
            grid[b][v] = 'O';
            grid[g][f] = 'X';
            cout << grid[x][y] << " ";
        }
        cout << endl;
    }
    if (grid[0][0] == grid[0][1] == grid[0][2] || grid[1][0] == grid[1][1] == grid[1][2] || grid[2][0] == grid[2][1] == grid[2][2])
    {
        cout << "Game Over! \n\n";
    }
    int i;
    cout << "Enter column number. \n";
    cin >> i;
    int u;
    cout << "Enter row number. \n";
    cin >> u;
    for (int y = 0; y < 3; y++)
    {
        for (int x = 0; x < 3; x++)
        {
            grid[x][y] = '-';
            grid[o][p] = 'X';
            grid[r][q] = 'O';
            grid[t][s] = 'X';
            grid[b][v] = 'O';
            grid[g][f] = 'X';
            grid[u][i] = 'O';
            cout << grid[x][y] << " ";
        }
        cout << endl;
    }
    if (grid[0][0] == grid[0][1] == grid[0][2] || grid[1][0] == grid[1][1] == grid[1][2] || grid[2][0] == grid[2][1] == grid[2][2])
    {
        cout << "Game Over! \n\n";
    }
    int a1;
    cout << "Enter column number. \n";
    cin >> a1;
    int e1;
    cout << "Enter row number. \n";
    cin >> e1;
    for (int y = 0; y < 3; y++)
    {
        for (int x = 0; x < 3; x++)
        {
            grid[x][y] = '-';
            grid[o][p] = 'X';
            grid[r][q] = 'O';
            grid[t][s] = 'X';
            grid[b][v] = 'O';
            grid[g][f] = 'X';
            grid[u][i] = 'O';
            grid[e1][a1] = 'X';
            cout << grid[x][y] << " ";
        }
        cout << endl;
    }
    if (grid[0][0] == grid[0][1] == grid[0][2] || grid[1][0] == grid[1][1] == grid[1][2] || grid[2][0] == grid[2][1] == grid[2][2])
    {
        cout << "Game Over! \n\n";
    }
    int a8;
    cout << "Enter column number. \n";
    cin >> a8;
    int b8;
    cout << "Enter row number. \n";
    cin >> b8;
    for (int y = 0; y < 3; y++)
    {
        for (int x = 0; x < 3; x++)
        {
            grid[x][y] = '-';
            grid[o][p] = 'X';
            grid[r][q] = 'O';
            grid[t][s] = 'X';
            grid[b][v] = 'O';
            grid[g][f] = 'X';
            grid[u][i] = 'O';
            grid[e1][a1] = 'X';
            grid[b8][a8] = 'O';
            cout << grid[x][y] << " ";
        }
        cout << endl;
    }
    if (grid[0][0] == grid[0][1] == grid[0][2] || grid[1][0] == grid[1][1] == grid[1][2] || grid[2][0] == grid[2][1] == grid[2][2])
    {
        cout << "Game Over! \n\n";
    }
    int a9;
    cout << "Enter column number. \n";
    cin >> a9;
    int b9;
    cout << "Enter row number. \n";
    cin >> b9;
    for (int y = 0; y < 3; y++)
    {
        for (int x = 0; x < 3; x++)
        {
            grid[x][y] = '-';
            grid[o][p] = 'X';
            grid[r][q] = 'O';
            grid[t][s] = 'X';
            grid[b][v] = 'O';
            grid[g][f] = 'X';
            grid[u][i] = 'O';
            grid[e1][a1] = 'X';
            grid[b8][a8] = 'O';
            grid[b9][a9] = 'X';
            cout << grid[x][y] << " ";
        }
        cout << endl;
    }
    if (grid[0][0] == grid[0][1] == grid[0][2] || grid[1][0] == grid[1][1] == grid[1][2] || grid[2][0] == grid[2][1] == grid[2][2])
    {
        cout << "Game Over! \n\n";
    }
}

Answer 1

在 C++ 中，== 符号的作用与它在代数类中的作用不同。表达式 a == b == c 在 C++ 中具有非常不同的含义。在 C++ 中，它仅适用于成对的项，并返回 true 或 false 值。 (更多信息见下文。)

要查看 3 个事物是否彼此相等，您需要说 (a == b && b == c)。您的网格检查需要如下所示:

if ( (grid[0][0] == grid[0][1] && grid[0][1] == grid[0][2]) || 
     (grid[1][0] == grid[1][1] && grid[1][1] == grid[1][2]) ||
     (grid[2][0] == grid[2][1] && grid[2][1] == grid[2][2]) )

您还会注意到我在其中放置了额外的括号。它们不是严格必需的，但是当您在同一表达式中混合使用 && 和 || 时，一些编译器会发出警告。括号清楚地表明您打算将哪些项目组合在一起，并将消除这些警告。

---

那么 C++ 编译器对您的代码做了什么？您已经编写了 grid[0][0] == grid[0][1] == grid[0][2]。根据 its operator precedence rules.，编译器将其解释为 (grid[0][0] == grid[0][1]) == grid[0][2]

编译器首先会比较grid[0][0]和grid[0][1]。这将产生一个 true 或 false bool 值 (C++ bool)，具体取决于它们是否相等。到目前为止，还不错。

比较后，它会将 bool 结果与 grid[0][2] 进行比较。由于 grid[0][2] 是一个 char，它会将 bool 提升为一个数值。 true 变为 1，false 变为 0。您的网格值都没有值 0 或 1 — 它们都是 '-'，'X' 或 'O'——所以第二次比较总是失败。

所有三行重复相同的情况。