java - 康维斯生命游戏 - 滑翔机模式在第一次突变后不起作用？

Question

我正在用 Java 开发 Conways Game of Life，但遇到了一些问题。

我的测试用例是滑翔机模式，但是当我尝试运行该程序时，滑翔机仅在第二代中第一次正确变异。第一次突变后的每一代都是不正确的，我不明白为什么。

Glider Should Mutate like this

This is what I get from running the code, the Glider shouldn't be stuck with a repeating pattern.

World.class(我的大部分方法都驻留在其中)

public class World extends Patterns
{

    private char [][] world;
    private char [][] tempWorld;
    private int numRows;
    private int numCols;

//World Constructor
    public World (int r, int c)
    {
        this.numRows = r;
        this.numCols = c;
        world = new char [r][c];
        tempWorld = new char [r][c];
        initalizeWorld();

    }

//Initializes the world and fills array with blank spaces
    private void initalizeWorld()
    {
        // Initialize all indexes to ' '
        for(int i = 0; i < numRows; i++) 
        {
            for(int j = 0; j < numCols; j++) 
            {
                world[i][j] = ' ';
            }
        }   
    }   


//Creates and stores data in a temp world for the next Generation
    public void nextGen()
    {
        for(int i = 0; i < numRows; i++) 
        {
            for(int j = 0; j < numCols; j++) 
            {
                changeCell(i,j);
            }
        }   
        world = tempWorld;      
    }

    //Prints world with *'s as Cells and O's as dead cells
    public void printWorld() 

    {
        // Print every value inside array 
        for(int i = 0; i < numRows; i++) 
        {
            for(int j = 0; j < numCols; j++) 
            {
                if(world[i][j] == '*')
                    System.out.print(" ");

                System.out.print(world[i][j]);

                if(world[i][j] != '*')
                {
                    System.out.print("O");
                }

            }
            System.out.println(" ");
        }
    }

    //Method check's for neighbors of a cell
    public int getNeighbors(int x, int y)
    {
        int numNeighbors = 0;

        for(int i = x - 1; i <= x + 1; i++)
        {
            for(int j = y - 1; j <= y + 1; j++)
            {

                if( (i >= 0) && (i < numRows) && (j < numCols) && (j >= 0))
                {                

                    if (world[i][j] == '*') 
                    {
                        numNeighbors++;
                    }

                }

            }
        }

        //don't count the cell itself
        return numNeighbors-1;

    }

    //Method uses getNeighbors to check whole array for every cells # of Neighbors
    public void checkAllNeighbors()
    {
        for(int i = 0; i < numRows; i++) 
        {
            for(int j = 0;j < numCols; j++) 
            {

                //if(world[i][j] == '*') 
                {
                    int neighbors = getNeighbors(i, j);
                    System.out.println("The cell at (" + i + ", " + j + ") has " + neighbors + " neighbors");
                }

            }
        }


    }

    //Method changes cell based on Neighbor Counts
    public void changeCell (int r, int c)
    {
        int count = getNeighbors(r,c);

        if (count == 3)
        {
            tempWorld [r][c] = '*';
        }
        else if (count >= 2 && count <= 3)
        {
            tempWorld [r][c] = '*'; 
        }
        else 
        {
            tempWorld [r][c] = ' ';
        }

    }

    //Gets world 
    public char [][] getWorld()
    {
        return world;
    }

    public void putGlider(int r, int c) 
    {
        char pattern[][] = getGlider();


        for (int i = 0; i < pattern.length; i++) 
        {
            for (int j = 0; j < pattern[0].length; j++)
            { 

                if ( (i + r < numRows) && (j + c < numCols) )
                {
                    world[i + r][j + c] = pattern[i][j];

                }
            }
        }
    }

}

Patterns.class(当前保存滑翔机图案，但稍后将容纳更多)

public class Patterns 
{
    private char[][] gliderArray = {{' ','*',' '},
                                   {' ',' ','*'},
                                   {'*','*','*'}};

    //private char [][] 

    public char[][] getGlider()
    {
        return gliderArray;
    }

}

test.class(我正在测试我的方法的地方)

    import java.util.Scanner;

public class test 
{
    public static void main(String[] args)
    {
        World test = new World (5,5);

        test.getWorld();
        test.putGlider(0,0);
        test.printWorld();

        System.out.println("Press enter to start generations!");
        new Scanner(System.in).nextLine();

        for(int i=0; i<10; i++)
        {
            test.nextGen();
            System.out.println(" ");
            test.printWorld();
            try 
            {
                Thread.sleep(2000);
            } catch (InterruptedException e) 
            {
                e.printStackTrace();
            }
        } 

    }

}

我已经在这个项目上工作了一段时间，但我真的陷入了困境。我不知道出了什么问题以及如何解决它，我开始有点生气。任何帮助将不胜感激!

谢谢!

基于 Sci Prog 建议的新 nextGen 方法，我不确定是否正确实现了循环中的循环。

public void nextGen()
{
    for(int i = 0; i < numRows; i++) 
    {
        for(int j = 0; j < numCols; j++) 
        {
            changeCell(i,j);
        }
    }   

    for (int r=0; r < this.numRows; r++)
          for (int c=0; c < this.numCols; c ++)
            world[r][c] = tempWorld[r][c];
}

我还更改了我的changeCell方法，但新的输出比我之前的输出更加偏离。

Answer 1

第一个问题

线路world = tempWorld;复制 tempWorld 的引用数组到world 。因此，两个变量都引用内存中的同一对象:在第一次迭代之后，每当您更改 tempWorld 中的元素时，它还会更改 world 中的相同元素.

您应该手动复制每个元素，即使它是较长的代码

for (int r=0; r < this.numRows; r++)
  for (int c=0; c < this.numCols; c ++)
    world[r][c] = tempWorld[r][c];

第二个问题

在你的changeCell中方法，您不检查当前单元格是“”还是“*”。 (活细胞=2或3，死细胞=3)

 //Method changes cell based on Neighbor Counts
public void changeCell (int r, int c)
{
    int count = getNeighbors(r,c);
    const char current = world[r][c];

    if ((current == ' ') && (count == 3))
    {
        tempWorld [r][c] = '*';
    }
    else if ((current=='*') && (count >= 2) && (count <= 3))
    {
        tempWorld [r][c] = '*'; 
    }
    else 
    {
        tempWorld [r][c] = ' ';
    }

}