如何检查二维数组是否超出界限?

The method isFilledAt() returns true if the shape has a filled block at the given row/col position and false if the block is empty. If the position is out of bounds, raise a FitItException with an informative message. Im running a nested loop to get the position and having trouble how to figure out if a position is out of bounds. Could smb help out? Thanks in advance!

如果在给定的行/col位置上有一个填充的块，如果块为空，则该方法将返回true。如果该位置超出了范围，请使用一个信息丰富的FitItException。我正在运行一个嵌套循环来获取位置，并且不知道如何判断一个位置是否超出了界限。smb可以帮助吗?提前谢谢!

public class CreateShape {

    private int height;
    private int width;
    private char dc;
    private Rotation initialPos;


    public CreateShape(int height, int width, char dc)
    {
        this.height = height;
        this.width = width;
        this.dc = dc;
        initialPos = Rotation.CW0;
    }
public boolean isFilledAt(int row, int col) 
    {
        char[][] tempArray = new char[height][width];
        for(int i = 0; i < tempArray.length; i++)
            for(int j = 0; j < tempArray[i].length; j++)
            {
                if(row > tempArray.length || row < 0)
                    throw new FitItException("Out of Bounds!");

                if(tempArray[row][col] == dc)
                    return true;
            }

        return false;
    }

2 个解决方案

#1

You need to check if the row or col are less than zero, or if row is greater than or equal to the height, or if col is greater than or equal to the width. Note you only need to do the validation once, so you could move the check outside the loop:

您需要检查行或col是否小于零，行是否大于或等于高，或者col是否大于或等于宽。注意，您只需要执行一次验证，因此可以将检查移出循环:

public boolean isFilledAt(int row, int col)  {
    if (row < 0 || row >= height || col < 0 || col >= width) {
        throw new FitItException("Out of Bounds!");
    }
    char[][] tempArray = new char[height][width];
    for (int i = 0; i < tempArray.length; i++) {
        for (int j = 0; j < tempArray[i].length; j++) {
            if (tempArray[row][col] == dc) {
                return true;
            }
        }
    }
    return false;
}

Note however that isFilledAt() may not work as you intend. Since you recreate tempArray every time you call the method, the condition tempArray[row][col] == dc will probably never evaluate to true.

但是请注意，isFilledAt()可能不能按照您的意愿工作。由于每次调用该方法时都要重新创建tempArray，因此条件tempArray[row][col] = dc可能永远不会计算为true。

#2

You should change your isFilledAt method as follows

您应该更改isFilledAt方法，如下所示

public boolean isFilledAt(int row, int col) 
{
    char[][] tempArray = new char[height][width];
    // Calls the method that fills tempArray datas

    if ( (row >= height || row <0)  || (col >= width || col < 0)) {
         throw new FitItException("Out of Bounds!");
    }

    for(int i = 0; i < height; i++)
        for(int j = 0; j < width; j++)
        {
                if(tempArray[row][col] == dc)
                return true;
        }


   }
   return false;
}

You place your return false at the wrong place: it would systematically return false if the looked up value was not inside the first row. Instead do a return false after every row has been iterated

您将return false放置在错误的位置:如果查找的值不在第一行中，则系统地返回false。相反，在遍历每一行之后执行返回false

#1