我無法弄清楚getExits()需要什么才能獲得問題請求的輸出。//構造函數public class Room { private String name; private String description; private Room north; private Room east; private Room south; private Room west; public Room (String name, String description){ this.name = name; this.description = description; } public Room getEast(){ return this.east; } public String getExits (){ // } public String getName(){ return this.name; } public Room getNorth(){ return this.north; } public Room getWest(){ return this.west; } public Room getSouth(){ return this.south; } public void setExits (Room n, Room e, Room w, Room s){ this.north = n; this.east = e; this.west = w; this.south = s; } public String toString(){ return String.format("%s\n%s\n%s", this.name, this.description,getExits()); }}//主要方法public class Tester{ public static void main(String []args){ Room hall = new Room ("Hall", "It's Dark"); Room bed = new Room ("Bed", "Tiny Room"); Room bath = new Room ("Bath", "Toilets here"); Room dine = new Room ("Dine", "Table and chairs"); hall.setExits(bed, bath, dine, null); System.out.println(hall); }}預期輸出：HallIt's DarkNorth: DineEast: BathWest: Dining
3 回答
繁花不似錦
TA貢獻1851條經驗 獲得超4個贊
獲得所需內容的“面向對象”方法是覆蓋類toString()中的方法Room，以便它返回房間的名稱。
然后修改getExits()，如下所示：
public String getExits (){
StringBuilder sb = new StringBuilder();
if(this.north != null) sb.append(this.north.toString()).append(" North") else sb.append("No Exit for: North");
...
return sb.toString();
}
....
public class Room {
private String name;
...
@Override
public String toString() {
return this.name;
}
}
ITMISS
TA貢獻1871條經驗 獲得超8個贊
exit不是您可以用String. 在 OO 世界中，它應該是對更有意義的對象的引用。我會和
public Collection<Room> getExits();
或者
public Map<String, Room> getExits();
它準確地描述了您可以從大廳到達哪里。在這里，我們假設“出口”是通往另一個房間的門口。
你可以回來
Arrays.asList(northRoom, eastRoom, southRoom, westRoom);
或者
Map<String, Room> map = new HashMap<>();
map.put("north", northRoom);
...
return map;
然后您將能夠提供String返回集合中的任何表示。
它就像一個放置在大廳里的標志，可以幫助人們導航。盡管它可以用另一個標志（更詳細/準確的標志）代替，但建筑物的結構是不變的，您不會改變它。您只是以不同的方式表示它。
String simpleSign = "You can go to: " + getExits().stream().map(Object::toString).collect(Collectors.join(", "));
或者
String detailedSign = "Directions to go: " + getExits().entrySet().stream().map(e -> e.getKey() + " -> " + e.getValue().toString()).collect(Collectors.join("\n"));
冉冉說
TA貢獻1877條經驗 獲得超1個贊
這是一種做事的方法。這有點尷尬，因為您必須為每種情況檢查 null - 如果不是這種情況，您可以刪除這些檢查。
public String getExits (){
List<String> exits = new ArrayList<>();
if (north != null) exits.add("North: " + north.name);
if (south != null) exits.add("South: " + south.name);
if (east != null) exits.add("East: " + east.name);
if (west != null) exits.add("West: " + west.name);
return String.join("\n", exits);
}
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