Question

在方法public boolean onMap(Coord c)中，如何确定给定的Coord c是否在此Map上（Map也是一个类）？这两个类都在下面。

 import java.io.*;
    import java.util.Scanner;
    public class Map {

        Spot[][] floorPlan;
        Thing[] things;
        java.io.PrintStream log;

        Map(String fileName, PrintStream log) throws IOException
        {
        String line = "";
        int cols = 0;
        int rows = 0;
        Scanner data = new Scanner(new File(fileName));
        while(data.hasNextLine())
        {
            line = data.nextLine();
            cols = line.length();
            rows++;
        }
        floorPlan = new Spot[rows][cols];
        }


        public boolean onMap(Coord c)
        {


            return true;
        }
    }


    public class Coord {

        public final int r;
        public final int c;


        public Coord(int r, int c)
        {
            this.r = r;
            this.c = c;
        }

        public Coord step(Direction d)
        {
            if(d == Direction.N)
            {
                Coord newValue = new Coord(r + 1, c);
                return newValue;
            }
            else if(d == Direction.S)
            {
                Coord newValue = new Coord(r - 1, c);
                return newValue;
            }
            else if(d == Direction.E)
            {
                Coord newValue = new Coord(r, c + 1);
                return newValue;
            }
            else if(d == Direction.W)
            {
                Coord newValue = new Coord(r, c - 1);
                return newValue;
            }

            else
                return this;

        }

        public Coord copy()
        {
            Coord clone = new Coord(r, c);
            return clone;

        }

        public boolean equals(Object o)
        {
            if(o instanceof Coord)
            {
                Coord newValue = (Coord)o;
                return this.r == newValue.r && this.c == newValue.c;
            }
            else 
                return false;
        }

        public boolean adjacent(Coord other)
        {
            Coord temp1 = new Coord(r + 1, c);
            Coord temp2 = new Coord(r - 1, c);
            Coord temp3 = new Coord(r, c + 1);
            Coord temp4 = new Coord(r, c - 1);

            if(temp1.r == other.r && temp1.c == other.c)
                return true;
            else if(temp2.r == other.r && temp2.c == other.c)
                return true;
            else if(temp3.r == other.r && temp3.c == other.c)
                return true;
            else if(temp4.r == other.r && temp4.c == other.c)
                return true;
            else 
                return false;

        }

        public String toString()
        {
            return String.format("\"@(%d,%d)\"", r,c);
        }


    }

Answer 1

蓝色的猜测是你想要做一些叫做边界检查的事情。（如果不是这样，请告诉我）

由于Spot[][]是一个数组数组，floorPlan[i]实际上是另一个数组（具有独立边界）。因此，检查是否

floorPlan[r][c]

不会抛出ArrayIndexOutOfBoundsException，您需要首先检查r上的floorPlan，然后c上的floorPlan[r]：

if (r < 0 || r >= floorPlan.length) return false;
if (c < 0 || c >= floorPlan[r].length) return false;
return true;

然而，实际提供Map属性width和height并始终强制执行floorPlan[r].length = width和floorPlan.length = height可能更为自然。为了获得更好的代码，你不应该从类外部提供私有变量，而是提供合理的getter和setter（甚至可以调整Map的大小而不丢失其内容的功能？）

如何检查传递的对象是否在地图上

1 个答案: