Question

我正在尝试制作一个从输入文本文件中获取二维数组的程序，因此我已经对其进行了修改。我认为它看起来不错，我一直在尝试不同的事情，到目前为止，我遇到的唯一问题是底部的主要方法，并使每种方法的打印功能都可以使用。顺便说一下，我正在Eclipse中进行此操作。出于某种原因，使用列表给我带来了问题，当我在main方法本身中设置了数组时，该程序正在运行，但是我一直在尝试对其进行修改，以使其获取文件。我想提供一种功能，让用户在stratup的命令行上输入文件名，如果没有提供命令行参数，则提示用户输入文件名。所以我认为我走的路正确，但不确定。

import java.io.*;
import java.io.FileNotFoundException;
import java.util.Scanner;

import javax.swing.JOptionPane;

public class TwoDimArray
{
    private static int[][] twodim;
    public TwoDimArray() {
        loadArray();
    }
    
    
    //main function
    
    public static int getTotal(int [][]numbers)
    {
        int tot=0;
        for(int row=0;row<numbers.length;row++)
            for(int col=0;col<numbers[row].length;col++)
                tot+=numbers[row][col];
        return tot;
    }
    
    public static double getAverage(int [][]numbers)
    {
        double avg;
        avg= (double)(getTotal(numbers)/(12));
        return avg;
    }
    public static int getRowTotal(int [][]numbers, int index)
    {
        int tot=0;
        for(int col=0;col<4;col++)
            tot+=numbers[index][col];
        return tot;
    }
    public static int getColumnTotal (int [][]numbers, int index)
    {
        int tot=0;
                for(int row=0;row<numbers.length;row++)
                    tot+=numbers[row][index];
        
        return tot;
    }
    
    public static int getHighest(int [][]numbers,int row)
    {
        int high=numbers[row][0];
        for(int i=1;i<numbers[row].length;i++)
            if(numbers[row][i]>high)
                high=numbers[row][i];
        return high;
    
    }
    public static int getLowest(int [][]numbers,int row)
    {
        int low=numbers[row][0];
        for(int i=1;i<numbers[row].length;i++) 
        
            if(numbers[row][i]<low)
                low=numbers[row][i];
        return low;
    }
    
    
    public void loadArray() {
        String fileName = "";
        
        try {
            fileName = JOptionPane.showInputDialog("Enter an input file name: ");
            
            if (fileName == null)
                throw new NullPointerException("Please do not press cancel!");
            
            Scanner infile = new Scanner(new File("input.txt"));
            
            if (!infile.hasNextLine()) {
                JOptionPane.showMessageDialog(null, "The input file " + fileName + " is empty!");
                System.exit(1);
            }else {
                infile.reset();
                
                String strRows = infile.next();
                String strCols = infile.next();
                
                int rows = Integer.parseInt(strRows);
                int cols = Integer.parseInt(strCols);
                
                twodim = new int[rows][cols];
                
                for (int i = 0; i < rows; i++) {
                    for (int j = 0; j < cols; j++) {
                    String data = infile.next();
                    twodim[i][j] = Integer.parseInt(data);
                    
                }
            }
            infile.close();
        }
    } catch (NullPointerException npe) {
        JOptionPane.showMessageDialog(null, npe.getMessage());
        System.exit(1);
    } catch (NumberFormatException nfe) {
        JOptionPane.showMessageDialog(null, "cannot convert input to integer");
        System.exit(1);
    }catch (FileNotFoundException fnfe) {
        JOptionPane.showMessageDialog(null,  "The input file " + fileName + " doesn't exist!");
        System.exit(1);
    }
        
    }
        

    

    public static void main (String []arg)
        {
            //private int[][] twodim;
            //int [][]list= {{1,2,3,4},{5,6,7,8},{9,10,11,12}};
            //Function call and display data returned
        
        TwoDimArray tda = new TwoDimArray();
        
            System.out.println("Total:"+getTotal(list));
            System.out.println("Average:"+getAverage(list));
            System.out.println("Row 2 value:"+getRowTotal(list,2));
            System.out.println("Column 3 Total :"+getColumnTotal(list,3));
            System.out.println("Highest value in row 1 is :"+getHighest(list,1));
            System.out.println("Lowest value in row 2 is :"+getLowest(list,2));
            
            //Exit program
            System.exit(0);
        }
}

Answer 1

此方法将打印2个暗淡的数组：

public void printMatrix(int[][] matrix) {
    for (int row = 0; row < matrix.length; row++) {
        for (int col = 0; col < matrix[0].length; col++) {
            System.out.print(matrix[row][col] + "\t");
        }
        System.out.println();
    }
}

我的二维数组程序的打印输出遇到问题

1 个答案: