我else if語句可在心不是我的井字程序工作

Question

//主代碼

公共靜態無效的主要（字串[] args）{

//初始化遊戲板

initGame(); 
    //start the game 
    do { 
     PlayerMove(Cplayer); 
     updategame(Cplayer, crow, ccol); 
     printboard(); 
     //game over message 
     if (currentstate == you_win){ 
      System.out.println("'X' Won!!"); 
      else if (currentstate == comp_win) 
       System.out.println("'O' won!!"); 
       else if (currentstate == draw) 
       System.out.println("It's a Draw :("); 
     } 

Answer 1

if (currentstate == you_win){ 
     System.out.println("'X' Won!!"); 
     else if (currentstate == comp_win) 
      System.out.println("'O' won!!"); 
      else if (currentstate == draw) 
      System.out.println("It's a Draw :("); 
    } 

看一下這一行（我刪除了一些無關的代碼，使其更容易看清）：

if (currentstate == you_win){ 
     else if (currentstate == comp_win) 
      //... 
    } 

用這種方式看，你能看出爲什麼這是不正確的嗎？順便說一句，這就是爲什麼你應該總是使用{和}。做if ... else這樣，而不是：

if (currentstate == you_win){ 
     // ... 
} 
else if (currentstate == comp_win) { 
    // ... 
    } 
    //... 

，或者甚至更好，只使用一個switch聲明：

switch (currentstate) { 
     case you_win: 
      System.out.println("'X' Won!!"); 
      break; 
     case comp_win: 
      System.out.println("'O' won!!"); 
      break; 

     case draw: 
      System.out.println("It's a Draw :("); 
      break; 
}