java - 如何确定文本文件中的藏宝图(行和列)有多大？

Question

我想知道如何计算出传递的文本文件的行和列。假设文本文件如下所示:

X...................
....................
....................
....................
....................
....................
....................
....................
....................
..X.................

这个文本文件有 10 行和 20 列，我在如何为我的构造函数获取这些行和列方面遇到了麻烦(不要担心“X”符号)。我只是想知道如何从文本文件中获取行和列/想知道如何计算出 map 有多大。

我需要有关代码中第二个构造函数的帮助:

import java.util.Scanner;   // Required to get input
import java.io.File;        // Required to get input from files



    // A 2D treasure map which stores locations of treasures in an array
    // of coordinates
    public class TreasureMap{
        int rows, cols;     // How big is the treasure map
        Coord [] treasureLocations; // The locations of treasures

        Scanner kbd = new Scanner(System.in);
      // Prompt the user for info on the treasure map and then create it

      public TreasureMap(){

          int numberOfTreasures = 0;
          System.out.println("Enter map size (2 ints): ");
          rows = kbd.nextInt(); cols = kbd.nextInt();
          System.out.println("Enter number of treasures (1 int): ");
          numberOfTreasures = kbd.nextInt();

          treasureLocations = new Coord[numberOfTreasures];

          for (int i = 0; i < numberOfTreasures; i++)
          {
              System.out.println("Enter treasure " + i + " location (2 ints): ");
              rows = kbd.nextInt(); cols = kbd.nextInt();
              treasureLocations[i] = new Coord(rows, cols);
          }
      }



      // Read the string representation of a map from a file

      public TreasureMap(String fileName) throws Exception{

          Scanner data = new Scanner(new File(fileName));
          int counter = 0;
          while(data.hasNextLine())
          {
            counter++;  
          }


      }



      // true if there is treasure at the given (r,c) coordinates, false
      // otherwise
      // This method does not require modification
      public boolean treasureAt(int r, int c){
        for(int i=0; i<treasureLocations.length; i++){
          Coord coord = treasureLocations[i];
          if(coord.row == r && coord.col == c){
        return true;
          }
        }
        return false;
      }

      // Create a string representation of the treasure map

      public String toString(){
        String [][] map = new String[this.rows][this.cols];
        for(int i=0; i<rows; i++){
          for(int j=0; j<cols; j++){
                map[i][j] = ".";
          }
        }
        for(int i=0; i<treasureLocations.length; i++){
          Coord c = treasureLocations[i];
          map[c.row][c.col] = "X";
        }
        StringBuilder sb = new StringBuilder();
        for(int i=0; i<rows; i++){
          for(int j=0; j<cols; j++){
        sb.append(map[i][j]);
          }
          sb.append("\n");
        }
        return sb.toString();
      }

    }

Answer 1

以下是一些可用于从文件中读取行的代码:

File file = new File(fileName);
try (BufferedReader br = new BufferedReader(new FileReader(file))) {
    String line;
    int rows = 0;
    int cols = 0;
    while ((line = br.readLine()) != null) {
        // process the line
        rows++;
        cols = line.length(); // always the size of the last line in the file
    }
}
br.close();