java - 为什么我的数组不满足该 if 语句的条件？

Question

我正在为一项作业执行此程序，但我完全不知道为什么我的数组(从单独的文件中读取值)无法满足此 if 语句的条件。 为了您的方便，相关语句位于 displayColonies 类中。

当我读取数组时，它会查找指定行和列的值，该值是从 1-9(含 1-9)注册的 int 值。当我使用 print 语句定期测试这一点时，数组确实包含正确的值，但 if 语句从未被激活。条件与数组的值匹配，但永远不会评估该语句，true 或其他。

感谢您的帮助。

代码附在下面: DetectColonies2ElectricBoogaloo 是客户端 幻灯片是对象 Slide.dat是文本文件，排列如下

6
8
10550000
00050000
00005500
01200000
01111000
00000030

public class DetectColonies2ElectricBoogaloo {

    public static void main(String [] args) {

        Slide culture = new Slide("Slide.dat");
        culture.displaySlide();
        culture.displayColonies();
   }
}

import java.io.*;

public class Slide {

    private char NON_COLONY = '0';
    private char [][] slideData;

    /**
     * constructor
     * pre: Slide file contains valid slide data in the format:
     * first line: lenght of slide
     * second line: width of slide
     * remaining lines: slide data
     * post: Slide data has been loaded from slide file.
     */
    public Slide(String s) {    
        try {
            File slideFile = new File(s);
            FileReader in = new FileReader(slideFile);
            BufferedReader readSlide = new BufferedReader(in);

            int length = Integer.parseInt(readSlide.readLine());
            int width = Integer.parseInt(readSlide.readLine());
            slideData = new char[length][width];

            for (int row = 0; row < length; row++) {
                for (int col = 0; col < width; col++) {
                    slideData[row][col] = (char)readSlide.read();
                }
                readSlide.readLine();   //read past end-of-line characters
            }
            readSlide.close();
            in.close();
       } catch (FileNotFoundException e) {
            System.out.println("File does not exist or could not be found.");
            System.err.println("FileNotFoundException: " + e.getMessage());
        } catch (IOException e) {
            System.out.println("Problem reading file.");
            System.err.println("IOException: " + e.getMessage());
        }
    }

    /**
     * Determines a colony size
     * pre: none
     * post: All colony cells adjoining and including cell (Row, Col) have 
     * been changed to NON_COLONY, and count of these cells is returned.
     */
    private int collectCells(int row, int col , char colour) {

        if ((row < 0) || (row >= slideData.length) || (col < 0) || (col >= slideData[0].length) || (slideData[row][col] != colour)) {
            return(0);
        } else {
            slideData[row][col] = NON_COLONY;
            return(1 + 
                collectCells(row + 1, col , colour) + 
                collectCells(row - 1, col , colour) + 
                collectCells(row, col + 1 , colour) + 
                collectCells(row, col - 1 , colour) + 
                collectCells(row - 1 , col - 1 , colour) + 
                collectCells(row + 1 , col + 1 , colour) + 
                collectCells(row - 1 , col + 1 , colour) + 
                collectCells(row + 1 , col - 1 , colour));
        }
    }

    /**
     * Analyzes a slide for colonies and displays colony data
     * pre: none
     * post: Colony data has been displayed.
     */
    public void displayColonies() {
        int count;
        System.out.format("%-10s %-10s %-10s" , "LOCATION" , "SIZE" , "COLOUR");
        System.out.println();

        for (int row = 0; row < slideData.length; row++) {
            for (int col = 0; col < slideData[0].length; col++) {
                for (int i = 1; i <= 9; i++) {
                    if (slideData[row][col] == i) {
                        count = collectCells(row , col , (char)i);
                        System.out.format("%-10s %-10s %-10s" , "(" + row + "," + col + ")" , count , i);
                    }
                }
            }
        }
    }


    /**
     * Displays a slide.
     * pre: none
     * post: Slide data has been displayed.
     */
    public void displaySlide() {

        for (int row = 0; row < slideData.length; row++) {
            for (int col = 0; col < slideData[0].length; col++) {
                System.out.print(slideData[row][col]);
            }
            System.out.println();
        }
    }
}

Answer 1

您正在将 int(i 中的值)(例如 3)与字符(如“1”、“2”...)(slideData中的值)进行比较code>)，整数是从 0x30 ('0') 开始的值..

因此，无需重写程序，最简单的解决方案就是通过将 for 循环值 (1..9) 转换为等效字符来修复不兼容的类型，如下所示:

for (int i = 1; i <= 9; i++)
{
    char x = (char) (0x30 + i);
    if (slideData[row][col] == x)
    {
       // ...
    }
}

要将整数(数字)转换为 char，您还可以执行以下操作:

  char x = Character.forDigit(i, 10);