我听说可以将if / else语句转换为循环，它们有点等同。有人可以给我一个例子，因为我很难理解转换过程。
根据评论，我想我没有正确地提出这个问题。我基本上正在完成一项任务，必须使用在所有if / else语句中编写的某人代码，并将其转换为包含循环的代码。
我不是要问这个问题的答案，但是我想问一个如何做到这一点的例子。我有很多方法可以做到这一点，下面是代码。它基本上是一个鬼屋迷宫式的“游戏”，只要你在经过房间后触摸和探索物体就会结束，但没有回溯。使用循环我必须允许回溯，并允许用户探索尽可能多的项目，并且只有在用户决定结束时才结束游戏。
编辑：
好的，我已经开始将上面代码的Living Room部分路径转换为while循环。请告诉我它是否看起来不错，如果我能以某种方式改进它，或者如果我犯了任何错误，它似乎运行正常。我唯一的问题是，当我点击决定去使用胸部时，它要求两次然后结束，它应该只询问一次，与烛台一样。也许我错过了一些关于“休息”的声明？但我不知道，因为当我在食品室里，然后回去，我还有其他只包含休息;它做了应该做的事情......但不是胸部和烛台。
但到目前为止，这是我的代码：
public class LoopyHauntedHouse {
private String name; //Player name.
private String location0; //First location selected from door.
private String toFrontDoor = "";
private String atFrontDoor;
//Method asking for user's name, and welcoming the user as well as asking where they'd like to go for the first time.
public void intro()throws MalformedURLException
{
//URL to image initialized from the original code as needed.
URL frontDoor = new URL("http://i.imgur.com/2m3giQk.png");
//Scanner for user input.
Scanner scnr = new Scanner(System.in);
//Asking for user's name and welcoming the user.
name = JOptionPane.showInputDialog(null, "What is your name?");
JOptionPane.showMessageDialog(null, "Welcome " + name + " to the Haunted House!");
//Shows starting location.
JOptionPane.showMessageDialog(null, name + " you're at the front door of the haunted house.", "Title",
JOptionPane.PLAIN_MESSAGE, new ImageIcon(frontDoor));
//Asks for first choice of room to start at.
location0 = JOptionPane.showInputDialog(null, name + " where to next? 'Living Room', 'Dining Room' or 'Stairs'?");
}
//Method for the rest of the program allowing users to walk through the house, backtrack, and interact with objects.
public void startWalking()throws MalformedURLException
{
//URLs to images are initialized from the original code as needed.
URL stairs = new URL("http://i.imgur.com/WuddJUc.png");
URL bedroom1 = new URL("http://i.imgur.com/HZ6OSyZ.png");
URL bedroom2 = new URL("http://i.imgur.com/JZORNpd.png");
URL bathroom = new URL("http://i.imgur.com/onSEc1J.png");
URL masterBedroom = new URL("http://i.imgur.com/bf4L0sH.png");
URL masterBathroom = new URL("http://i.imgur.com/yp87dTX.png");
URL livingRoom = new URL("http://i.imgur.com/7XQD5Pt.png");
URL bathRoom = new URL("http://i.imgur.com/G0CxjSy.png");
URL diningRoom = new URL("http://i.imgur.com/gyU9mep.png");
URL kitchen = new URL("http://i.imgur.com/tTMRCID.png");
URL pantry = new URL("http://i.imgur.com/zBxPJCs.png");
while(location0.equalsIgnoreCase("Living Room")||(toFrontDoor.equalsIgnoreCase("Living Room")))
{
JOptionPane.showMessageDialog(null, name + " you are now in the Living Room");
String move1 = JOptionPane.showInputDialog(null, name + " would you like to explore the 'Chest' walk to the 'Bathroom' or 'Go back' and go to another room?");
if(move1.equalsIgnoreCase("Chest"))
{
JOptionPane.showMessageDialog(null, name + " a ghost escapes and scares you to death!");
JOptionPane.showMessageDialog(null, "Game Over! You've died.", "Try Again.",
JOptionPane.WARNING_MESSAGE, new ImageIcon(livingRoom));
break;
}
else if(move1.equalsIgnoreCase("Bathroom"))
{
while(move1.equalsIgnoreCase("Bathroom"))
{
JOptionPane.showMessageDialog(null, name + " you are now in the bathroom.");
String move2 = JOptionPane.showInputDialog(null, name + " would you like to explore the 'Mirror', 'Shower', or 'Go back'?");
if(move2.equalsIgnoreCase("Shower"))
{
JOptionPane.showMessageDialog(null, name + " the room suddenly steams up and you feel fingers touching the back of your neck...");
}
else if(move2.equalsIgnoreCase("Mirror"))
{
JOptionPane.showMessageDialog(null, name + "you see a bloody face looking back at you!");
}
else if(move2.equalsIgnoreCase("Go back"))
{
JOptionPane.showMessageDialog(null, name + " you are now in the Living Room");
break;
}
else
{
JOptionPane.showMessageDialog(null, "Please enter a valid option.");
}
}
}
else if(move1.equalsIgnoreCase("Go back"))
{
toFrontDoor = move1;
break;
}
else
{
JOptionPane.showMessageDialog(null, "Please enter a valid option.");
}
}
while(location0.equalsIgnoreCase("Dining Room"))
{
JOptionPane.showMessageDialog(null, name + " you are now in the Dining Room");
String move1 = JOptionPane.showInputDialog(null, name + " would you like to explore the 'Candelabra' or walk to the 'Kitchen'");
if(move1.equalsIgnoreCase("Candelabra"))
{
JOptionPane.showMessageDialog(null, "The candelabra light up by themselves and " + name + " sees a death shadow!");
JOptionPane.showMessageDialog(null, "Game Over! You've died.", "Try Again.",
JOptionPane.WARNING_MESSAGE, new ImageIcon(diningRoom));
break;
}
else if(move1.equalsIgnoreCase("Kitchen"))
{
while(move1.equalsIgnoreCase("Kitchen"))
{
JOptionPane.showMessageDialog(null, name + " you are now in the 'Kitchen'.");
String move2 = JOptionPane.showInputDialog(null, name + " would you like to explore either the 'Refrigerator' or 'Cabinet' walk to the 'Pantry', or 'Go back'");
if(move2.equalsIgnoreCase("Refrigerator"))
{
JOptionPane.showMessageDialog(null, name + " opens the refrigerator and finds some delicious soul food.");
}
else if(move2.equalsIgnoreCase("Cabiner"))
{
JOptionPane.showMessageDialog(null, "The dished and glasses start flying at you as soon as you open the door. " + name + " gets hit in the head and feels themselves moving towards a light.");
JOptionPane.showMessageDialog(null, "Game Over! You've died.", "Try Again.",
JOptionPane.WARNING_MESSAGE, new ImageIcon(kitchen));
break;
}
else if(move2.equalsIgnoreCase("Pantry"))
{
while(move2.equalsIgnoreCase("Pantry"))
{
JOptionPane.showMessageDialog(null, name + " you are now in the Pantry.");
String move3 = JOptionPane.showInputDialog(null, name + " would like to explore the 'Dusty Recipe Box', the 'Broom', or 'Go back'?");
if(move3.equalsIgnoreCase("Dusty Recipe Box"))
{
JOptionPane.showMessageDialog(null, name + "opens it up and a recipe for chocolate devils food cake appears out of no where.");
}
else if(move3.equalsIgnoreCase("Broom"))
{
JOptionPane.showMessageDialog(null, "As soon as " + name + " touches the broom, it flies up in the air!");
}
else if(move3.equalsIgnoreCase("Go back"))
{
break;
}
else
{
JOptionPane.showMessageDialog(null, "Please enter a valid option.");
}
}
}
else if(move2.equalsIgnoreCase("Go back"))
{
toFrontDoor = move2;
break;
}
else
{
JOptionPane.showMessageDialog(null, "Please enter a valid option.");
}
}
}
}
}
public void toFrontDoor() throws MalformedURLException
{
if(toFrontDoor.equalsIgnoreCase("Go back"))
{
atFrontDoor = JOptionPane.showInputDialog(null, name + " where to next? 'Living Room', 'Dining Room', 'Stairs', or 'Leave the house'?");
if(atFrontDoor.equalsIgnoreCase("Leave the house"))
{
JOptionPane.showMessageDialog(null, "Game Over! Thanks for playing.");
}
}
else
{
startWalking();
}
}
}
测试CLass：
public class LoopyTest {
public static void main(String[] args) throws MalformedURLException {
LoopyHauntedHouse player = new LoopyHauntedHouse();
player.intro();
player.startWalking();
player.toFrontDoor();
}
}
答案 0 :(得分：2)
是的，在汇编语言中，循环使用condition语句和goto语句实现：
L1: if ( <cond> )
{
<loop-body>
goto L1 ;
}
您可以在C中使用此方法，但不能在Java中使用，因为不允许使用goto。
当程序到达L1时，它会检查条件。如果条件满足，程序将继续循环体，之后它将跳转（转到）L1，标记程序中的行号。在那里，一个循环。如果条件不满足则会中断，程序将在大括号{之后的下一行继续。
答案 1 :(得分：1)
如果你要小心设计它，你可以创建一个与if语句功能相同的循环。
如果
if(myVal == 1) {
//do something
}
功能相同的 ：
for(int i = myVal; i == 1; ++i) {
//Do something
}
功能相当的而：
int i = myVal;
while(i == 1) {
//Do something
++i;
}
注意，在循环中我不直接将myVal与循环终止符进行比较。这是因为您必须更改比较值才能退出循环，并且您可能不想更改实际变量。
但是，如果您的整个所需代码都在while(isPlaying) {}内运行，那么您就不需要一堆其他循环。您只需为每次移动检查的所有地点添加else if(move#.equalsIgnoreCase("quit") {isPlaying = false; }。
我还想补充一点，您当前的代码可以从使用类中受益。对于用户输入的每个命令，没有理由拥有新的move＃变量。
答案 2 :(得分：0)
由于不同的房间是一种“状态”。你可以在使用state pattern时解决它。每个州由一个对象表示。使用这些对象，每个对象可以根据它的状态决定下一步做什么。例如：
class Room {
private String roomName;
private URL icon;
private List<String> nextRooms;
public Room(String _roomName, URL _icon, String... _nextRooms) {
roomName = _roomName;
icon = _icon;
nextRooms = new ArrayList<>();
for (String string : _nextRooms) {
nextRooms.add(string.toLowerCase());
}
}
public void showInfo(String player) {
JOptionPane.showMessageDialog(null, player + " you're in " + roomName, "Title",
JOptionPane.PLAIN_MESSAGE, new ImageIcon(icon));
}
public String nextRoomName(String player) {
StringBuilder sb = new StringBuilder();
for (String string : nextRooms) {
sb.append(string).append(", ");
}
String roomOptions = sb.toString();
while(true) {
String input = JOptionPane.showInputDialog(null, player + " where to next? Your options are: " + roomOptions);
if(nextRooms.contains(input)) {
return input;
}
}
}
}
public void start() throws MalformedURLException {
Map<String, Room> rooms = new HashMap<>();
rooms.put("room a", new Room("Room A", new URL("http://i.imgur.com/7XQD5Pt.png"), "Room B", "Room C"));
rooms.put("room b", new Room("Room B", new URL("http://i.imgur.com/7XQD5Pt.png"), "Room A"));
rooms.put("room c", new Room("Room C", new URL("http://i.imgur.com/7XQD5Pt.png"), "Room A", "Win"));
String player = JOptionPane.showInputDialog(null, "What is your name?");
JOptionPane.showMessageDialog(null, "Welcome " + player + " to the Haunted House!");
Room room = rooms.get("room a");
while (true) {
room.showInfo(player);
String nextRoom = room.nextRoomName(player).toLowerCase();
if ("win".equalsIgnoreCase(nextRoom)) {
return;
}
if (rooms.containsKey(nextRoom)) {
room = rooms.get(nextRoom);
}
}
}
这有点复杂，特别是如果你是Java或面向对象的新手，所以或者让每个房间成为一种方法。根据用户的决定，调用适当的方法等等。
void start() {
roomA();
}
void roomA() {
String input = JOptionPane....
if (input.equals("Room B")) {
roomB();
}
}
void roomB() {
String input = JOptionPane....
if (input.equals("Room A")) {
roomA();
} else if (input.equals("win")) {
win();
}
}
void win() {
JOptionPane.showMessageDialog...
}