Question

import java.io.*;
public class Point {
    private double x;
    private double y;
    public Point(double x_coord, double y_coord) {
        x = x_coord;
        y = y_coord;
    }
}
public class PointArray {
    private Point points[];
    public PointArray(FileInputStream fileIn) throws IOException {
        try {
            BufferedReader inputStream = new BufferedReader(new InputStreamReader(fileIn));
            int numberOfPoints = Integer.parseInt(inputStream.readLine())...points = new Point[numberOfPoints];
            int i = 0;
            String line;
            while ((line = inputStream.readLine()) != null) {
                System.out.print(line);
                double x = Double.parseDouble(line.split(" ")[0]);
                double y = Double.parseDouble(line.split(" ")[1]);
                points[i] = new Point(x, y);
                i++;
            }
            inputStream.close();
        } catch (IOException e) {
            System.out.println("Error");
            System.exit(0);
        }
    }
}
public String toString() {
    String format = "{";
    for (int i = 0; i < points.length; i++) {
        if (i < points.length - 1) format = format + points[i] + ", ";
        else format = format + points[i];
    }
    format = format + "}";
    return format;
}
public static void main(String[] args) {
    FileInputStream five = new FileInputStream(new File("fivePoints.txt"));
    PointArray fivePoints = new PointArray(five);
    System.out.println(fivePoints.toString());
}

txt文件fivePoints如下所示：

第一行中的第一个数字表示文本文件中的点数。读取文件时出错。我想得到的输出是{（2.0,7.0），（3.0,5.0），（11.0,17.0），（23.0,19.0），（150.0,1.0）}。我该如何解决？

Answer 1

向toString添加Point方法，将Point格式化为x, y

public class Point {
    //...        
    @Override
    public String toString() {
        return x + ", " + y;
    }
}

移动toString方法，使其在PointArray中定义，您也可以考虑使用StringJoiner让您的生活更简单

public class PointArray {
    //...
    @Override
    public String toString() {
        StringJoiner sj = new StringJoiner(", ", "{", "}");
        for (int i = 0; i < points.length; i++) {
            sj.add("(" + points[i].toString() + ")");
        }
        return sj.toString();
    }
}

无法读取txt文件

1 个答案: