如果語句在條件不滿足時觸發？

Question

我正在試圖製作一個使用2D陣列來玩井字遊戲的程序。我設置了一個while循環，其中兩個while循環來回傳遞，直到勝利條件滿足。基本上，while循環一直持續，直到滿足一個勝利條件（在一次完整的轉場之後立即發生）。其中兩個while循環代表圈數。因此，如果法律參數得到滿足，玩家輪到他們，然後玩家輪到他們，等等。如果參數不符合，那很好，它會回到該回合的頂部，以便他們可以再次嘗試。這裏是我的代碼：

#include <iostream> 
#include <cstdlib> 

using namespace std; 

int main() 
{ 
    char TicTacToe [3][3] = {0}; // This initializes an array of "e's" for empty space. 

    for (int i = 0; i < 3; i++) 
    { 
     for (int j = 0; j < 3; j++) 
     { 
      TicTacToe [i][j] = 'e'; 
     } 
    } 

    for (int i = 0; i < 3; i++) // This outputs the game board so the user(s) can get a visual. 
    { 
     for (int j = 0; j < 3; j++) 
     { 
      cout << TicTacToe [i][j] << " "; 
     } 
     cout << "\n"; 
    } 

    bool flag = true; 
    bool turn1flag = true; 
    bool turn2flag = true; 
    int p1row, p1col, p2row, p2col = 0; 

    cout << "\n"; 
    cout << "Welcome to Tic-Tac-Toe. The game board is shown above. " << endl; 
    cout << "The rows are numbered one through three from top to bottom. " << endl; 
    cout << "The columns are numbered one through three from left to right. " << endl; 
    cout << "Player one's spaces are indicated by an 'o.'" << endl; 
    cout << "Player two's spaces are indicated by an 'x.'" << endl; 
    cout << "Empty spaces are indicated by an 'e.'" << endl << endl; 

    while (flag == true) // This while loop starts the game 
    { 
     while (turn1flag == true) 
     { 
      cout << "It is player one's turn. Which row? " << endl; 
      cin >> p1row; 
      cout << "And which column? " << endl; 
      cin >> p1col; 

      if (TicTacToe[p1row-1][p1col-1] == 'e') // This checks if the selected spot is empty. If not, it's filled with the users symbol. 
      { 
       TicTacToe[p1row-1][p1col-1] = 'o'; 

       for (int i = 0; i < 3; i++) // This outputs the game board so the user(s) can see their progress. 
       { 
        for (int j = 0; j < 3; j++) 
        { 
         cout << TicTacToe [i][j] << " "; 
        } 
        cout << "\n"; 
       } 

       cout << "\n"; 

       turn1flag = false; 
      } 
      else // If a position is taken or out of bounds, we're returned to the top of the turn loop. 
      { 
       cout << "That position is already taken or out of bounds. Try again. " << endl; 
      } 
     } 

     while (turn2flag == true) 
     { 
      cout << "It is player two's turn. Which row? " << endl; 
      cin >> p2row; 
      cout << "And which column? " << endl; 
      cin >> p2col; 

      if (TicTacToe[p2row-1][p2col-1] == 'e') 
      { 
       TicTacToe[p2row-1][p2col-1] = 'x'; 

       for (int i = 0; i < 3; i++) // This outputs the game board so the user(s) can see their progress. 
       { 
        for (int j = 0; j < 3; j++) 
        { 
         cout << TicTacToe [i][j] << " "; 
        } 
        cout << "\n"; 
       } 

       cout << "\n"; 

       turn2flag = false; 
      } 
      else 
      { 
       cout << "That position is already taken or out of bounds. Try again. " << endl; 
      } 
     } 

     // All of the following are player one win conditions. 

     if ((TicTacToe [0][0] = 'o') && (TicTacToe [0][1] = 'o') && (TicTacToe [0][2] = 'o')) 
     { 
      cout << "Congratulations player one, you've won!" << endl; 
      flag = false; 
     } 
... // the other 15 winning conditions for either player 1 or 2. 

Answer 1

if ((TicTacToe [0][0] = 'o') && (TicTacToe [0][1] = 'o') && (TicTacToe [0][2] = 'o')) 

這些都是分配。您需要==而不是=。

這裏發生的是'o'被分配，然後在布爾上下文中使用。每個可見字符被視爲true，因此條件被視爲true && true && true，始終爲true。

Answer 2

您永遠不會將turn1flag和turn2flag重置爲真。正如它所寫的，它看起來會讓每個玩家都有一個回合，然後停止回合。你需要或是改變線路，像這樣：

turn1flag = false; 
turn2flag = true; 

和

turn2flag = false; 
turn1flag = true; 

或者只是使用一個單一的標誌，並有第一while循環檢查，如果這是真的，和第二檢查，如果它是假的。然後第二個循環可以在移動後將其設置回真。

最重要的是，您需要在if語句中使用==，否則您將分配值，該值將自動評估爲true。

Answer 3

您在if語句中使用賦值而不是比較。 =將返回賦值的值，只要該值不是0，它將被評估爲true。使用==來比較兩個值。