文本文件的最后一行未正确存储到2D数组中

问题描述 投票:0回答:1

我的扫描仪无法正确访问文本文件的最后一行,因此将文本文件的最后一行存储为全0,而不是实际存在的2D数组。我相信我已经提供了一切内容,可以提供正在发生问题的上下文,但是如果需要更多信息,我可以更新此问题,在此先感谢。

//Creates 2-d array object, stores values from file.
public DominoSort (String fileName) throws java.io.FileNotFoundException{
    this.grid = new int [7][8]; //2-d array to hold values from text file

    Scanner br = new Scanner(new File(fileName));
    String line = br.nextLine();

    int r = 0;
    int c = 0;

    while (br.hasNextLine) {
        String[] row = line.split("\\s+");
        for (String s : row) {
            this.grid[r][c] = Integer.parseInt(s);
            c++;
        }
        line = br.nextLine();
        r++;
        c = 0;
    }

    //this.setS = new ArrayList<>();
    //this.pairMappings = new ArrayList<ArrayList<dominoLocation>>();

    br.close();
}

//Print grid function, prints out the grid
public void printGrid() {
    for(int r = 0; r < this.grid.length; r++) {
        System.out.println("");
        for(int c = 0; c < this.grid[r].length; c++) {
            System.out.print(this.grid[r][c] + " ");
        }
    }
    System.out.println("");
}

//Driver for checking
public static void main(String[] args) throws IOException {
    // String line;
    //System.out.println(new File(".").getAbsolutePath());
    Scanner input = new Scanner(System.in); //get textfile name from user input
    System.out.print("Enter the file name: ");
    String fileName = input.next();

    DominoSort dom = new DominoSort(fileName); //this call populates the 2-d array object
    //dom.solvePuzzle(6);
    dom.printGrid(); //prints 2d array for output

    //dom.solvePuzzle(6);
}

用于测试的文本文件/预期输出:

3 3 4 2 2 0 0 0
4 6 3 6 3 1 4 1
5 5 4 1 2 1 6 5
5 6 0 2 1 1 5 3
5 4 4 2 6 0 2 6
3 0 4 6 6 1 3 1
2 0 3 2 5 0 5 4    {Notice this line}

实际输出:

3 3 4 2 2 0 0 0
4 6 3 6 3 1 4 1
5 5 4 1 2 1 6 5
5 6 0 2 1 1 5 3
5 4 4 2 6 0 2 6
3 0 4 6 6 1 3 1
0 0 0 0 0 0 0 0    {this line is not right}
java arrays java.util.scanner
1个回答
0
投票

您的问题位于嵌套的while / for循环内。在读取所有行之前达到终止条件。 (在读取最后一行之前,nextLine()方法没有更多的行了)。您可以通过在文件的末尾额外添加1或2行,使其显示最后几行来看到此内容。有几种方法可以解决它,其中一种是在while循环之后仅添加一个额外的for循环来分别计算最后一行:

    while (br.hasNextLine()) {

        String[] row = line.split("\\s+");

        for (String s : row) {
            this.grid[r][c] = Integer.parseInt(s);
            c++;
        }

        line = br.nextLine();
        r++;
        c = 0;
    }

    String[] row = line.split("\\s+");
    for (String s : row) {
        this.grid[r][c] = Integer.parseInt(s);
        c++;
    }

或者,在第一次运行时不要增加行数:

        while (br.hasNextLine()) {

            String[] row = line.split("\\s+");

            for (String s : row) {
                this.grid[r][c] = Integer.parseInt(s);
                c++;
            }

            if (r != 0) 
                line = br.nextLine();

            r++;
            c = 0;
        }
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