Question

我正在尝试做这个项目，出于某种原因，我遇到的问题是，对于我的生活我无法解决。

public static void printlist(String n){
    for(int i=0; i<  roomlist.size(); i++){
        if(roomlist.get(i).name.equals(n)){
            System.out.println("Room Name: " + roomlist.get(i).name + " state:     " + roomlist.get(i).state);
            System.out.println("Description: " + roomlist.get(i).desc);
            System.out.println("Creatures in Room: " + roomlist.get(i).Fred());
            if(roomlist.get(i).north != null){
                System.out.println("North Neighbor: " + roomlist.get(i).north.name);
            }
            if (roomlist.get(i).south !=null){
                System.out.println("South Neighbor: " + roomlist.get(i).south.name);
            }
            if (roomlist.get(i).east !=null){
                System.out.println("East Neighbor: " + roomlist.get(i).east.name);
            }
            if (roomlist.get(i).west !=null){
                System.out.println("West Neighbor: " + roomlist.get(i).west.name);
            }
        }

    }
    System.out.println("Room " + n + " does not exist!");
}

现在，即使它在ArrayList中找到Room对象，它仍会打印“Room”+ n +“不存在！”我需要它只打印，如果在ArrayList中找不到房间

Answer 1

它发生的原因是因为Not found消息是您方法的最后一个语句。您应该在找到元素后立即从方法返回并打印出您想要的消息。

例如，假设每个房间都有一个唯一的名称：

...
if (roomlist.get(i).name.equals(n)) {
    ...
    if (roomlist.get(i).west != null) {
       System.out.println("West Neighbor: " + roomlist.get(i).west.name);
    }
    return;
}
...

Answer 2

基本上，System.out.println("Room " + n + " does not exist!");将始终执行，因为没有什么能阻止它

假设可能有多个相邻的房间，可能更容易使用简单的标志来指示是否找到了任何房间

public static void printlist(String n){
    boolean foundRoom = false;
    for(int i=0; i<  roomlist.size(); i++){
        if(roomlist.get(i).name.equals(n)){
            foundRoom = true;
            System.out.println("Room Name: " + roomlist.get(i).name + " state:     " + roomlist.get(i).state);
            System.out.println("Description: " + roomlist.get(i).desc);
            System.out.println("Creatures in Room: " + roomlist.get(i).Fred());
            if(roomlist.get(i).north != null){
                System.out.println("North Neighbor: " + roomlist.get(i).north.name);
            }
            if (roomlist.get(i).south !=null){
                System.out.println("South Neighbor: " + roomlist.get(i).south.name);
            }
            if (roomlist.get(i).east !=null){
                System.out.println("East Neighbor: " + roomlist.get(i).east.name);
            }
            if (roomlist.get(i).west !=null){
                System.out.println("West Neighbor: " + roomlist.get(i).west.name);
            }
        }

    }
    if (!foundRoom) {
        System.out.println("Room " + n + " does not exist!");
    }
}

你可以通过使用某种类型的List来存储相邻的房间并在最后检查size来优化它，但基本的想法仍然是相同的......

找不到东西时不要打印“未找到”

2 个答案: