java - 程序可以编译，但表格不会打印出来

Question

程序符合要求，但我无法打印结果表。该程序应该分析 1 和 0 的随机表，并打印出一个按顺序计算 1 数量的表。表大小由用户创建的输入生成。这工作正常，但我无法打印结果表。我感谢另一种类型的随机实用程序可能会起作用。

现在我得到一张满是零的表......

import java.util.Scanner;
import java.util.Random;

 public class Project1a {
    static int[][] results;   
    static int[][] sample;   

    static int goodData = 1;

    public static void main(String[] args) {   // main comes first (or last)
       scanInfo();
        analyzeTable();
       printTable(results);

    }


  public static void scanInfo()
     {
       Scanner input = new Scanner(System.in);
       System.out.println("Enter number of rows: ");   
       int rows = input.nextInt();
       System.out.println("Enter number of columns: ");
       int columns = input.nextInt();
       Random randomNumbers = new Random();
       sample = new int[rows= randomNumbers.nextInt(50)][columns = randomNumbers.nextInt(50)]; 
       results = new int[rows][columns];


    }



    static void analyzeTable() {   // no argument.  static var sample is assumed
       int row=0;
       while (row < sample.length) {
          analyzeRow(row);
          row++;
       }
    }
    static void analyzeRow(int row) {   // assume sample is "global"
       int xCol = 0;
       int rCount = 0;
       while (xCol < sample[row].length) {
          rCount = analyzeCell(row,xCol);
          results[row][xCol] = rCount; // instead of print
          xCol++;
       }
    }
    static int analyzeCell(int row, int col) {
       int xCol = col;  
       int runCount = 0; 
       int rowLen = sample[row].length;  
       int hereData = sample[row][xCol]; 
       while (hereData == goodData && xCol < rowLen) {
          runCount++;
          xCol++;
          if (xCol < rowLen) { hereData = sample[row][xCol];}
       }
       return runCount;
    }

   public static void printTable(int[][] aTable ) {
     for (int[] row : aTable) {

       printRow(row);
       System.out.println();
     }
   }
   public static void printRow(int[] aRow) {
     for (int cell  : aRow) {
       System.out.printf("%d ", cell);
     }
   }
 }

Answer 1

你的问题是这一行。

sample = new int[rows= randomNumbers.nextInt(1)][columns = randomNumbers.nextInt(2)];

你看，nextInt(1) 将始终返回 0，因此你将 rows 设置为零，最终得到几个没有行的数组完全没有。

来自 nextInt 的 Javadoc -

public int nextInt(int n)

Returns a pseudorandom, uniformly distributed int value between 0 (inclusive) and the specified value (exclusive), drawn from this random number generator's sequence.