switch語句和用戶輸入

Question

我正在寫一個程序，它從電影「千與千尋」中移動奇契羅的圖片。我目前所需要做的就是移動她的左，右，上，下。她有一個用戶輸入的初始位置。然後我的程序要求用戶輸入移動她的u/d/l/r。我如何提示用戶輸入重新移動她？它總是讓她移動並退出循環。

// Initial position 
Scanner keyboard = new Scanner(System.in); 
System.out.print("Starting row: "); 
int currentRow = keyboard.nextInt(); 
System.out.print("Starting column: "); 
int currentCol = keyboard.nextInt(); 

// Create maze 
Maze maze = new Maze(numberRows, numberCols, currentRow, currentCol); 

System.out.print("Move Chichiro (u/d/lr): "); 

char move = keyboard.next().charAt(0); 

switch (move){ 

    case 'u': maze.moveTo(--currentRow, currentCol); // move up 
     break; 
    case 'd': maze.moveTo(++currentRow, currentCol); // move down 
     break; 
    case 'l': maze.moveTo(currentRow, --currentCol); // move left 
     break; 
    case 'r': maze.moveTo(currentRow, ++currentCol); // move right 
     break; 
    default: System.out.print("That is not a valid direction!"); 

} 

Answer 1

放在一個while循環代碼，幷包括退出，就像擊中q關鍵的手段：

boolean quit=false; 

//keep asking for input until a 'q' is pressed 
while(! quit) { 
    System.out.print("Move Chichiro (u/d/l/r/q): "); 
    char move = keyboard.next().charAt(0);  

    switch (move){ 
    case 'u': maze.moveTo(--currentRow, currentCol); // move up 
       break; 
    case 'd': maze.moveTo(++currentRow, currentCol); // move down break; 
    case 'l': maze.moveTo(currentRow, --currentCol); // move left 
       break; 
    case 'r': maze.moveTo(currentRow, ++currentCol); // move right 
       break; 
    case 'q': quit=true; // quit playing 
       break; 
    default: System.out.print("That is not a valid direction!");}} 
    } 
} 

Answer 2

用下面的代碼，你可以移動，只要你想盡可能多的，當你要退出程序，你只需要輸入「q」：

 // Create maze 
    Maze maze = new Maze(numberRows, numberCols, currentRow, currentCol); 
    char move; 


    do{ 

      System.out.print("Move Chichiro (u/d/lr): "); 

     move = keyboard.next().charAt(0); 

     switch (move){ 

      case 'u': maze.moveTo(--currentRow, currentCol); // move up 
       break; 
      case 'd': maze.moveTo(++currentRow, currentCol); // move down 
       break; 
      case 'l': maze.moveTo(currentRow, --currentCol); // move left 
       break; 
      case 'r': maze.moveTo(currentRow, ++currentCol); // move right 
       break; 
      default: System.out.print("That is not a valid direction!"); 

     } 

    }while(move != 'q'); 

編輯：更正