I'm currently doing a model, however its occurred that I'm getting 1 error that which is saying that the && operator. I don't fully understand why that is. If there is a solution to this that would be great, also with a good explanation why I have made this mistake

Thanks

```
import java.awt.image.*;
import javax.imageio.*;
import java.io.File;
public class SlidingBlockModel
{
BufferedImage[][] board; // the two '[][]' allows a 2-D array to be created - each element is an image
int NUM_COLUMNS;
int NUM_ROWS;
int empty_col; // holds the column index of the one empty square
int empty_row; // holds the row index of the one empty square
int control[][];
SlidingBlockModel(int input_num_cols,int input_num_rows,String image_filename)
{
NUM_COLUMNS = input_num_cols;
NUM_ROWS = input_num_rows;
BufferedImage original_image = null;
board = new BufferedImage[NUM_COLUMNS][NUM_ROWS];
control = new int [NUM_COLUMNS][NUM_ROWS];
try
{
original_image = ImageIO.read(new File(image_filename));
}
catch (Exception e)
{
System.out.println("Sorry - couldn't load in file " + image_filename);
}
int block_width = original_image.getWidth()/NUM_COLUMNS;
int block_height = original_image.getHeight()/NUM_ROWS;
for (int i = 0;i<NUM_COLUMNS;i++)
for(int j = 0;j<NUM_ROWS;j++)
{
int x = block_width*i;
int y = block_height*j;
board[i][j] = original_image.getSubimage(x, y, block_width, block_height);
}
empty_row = NUM_ROWS-1;
empty_col = NUM_COLUMNS-1;
board[empty_col][empty_row] = null; // removes the sub-image that was there
}
boolean go(int col, int row)
{
if (((Math.abs(row-empty_row) == 1)&&(Math.abs(col-empty_col) != 1))||((Math.abs(row-empty_row)!= 1)&&(Math.abs(col-empty_col))))
{
board[empty_col][empty_row] = board[col][row];
control[empty_col][empty_row] = control[col][row];
board[col][row] = null;
empty_col = col;
empty_row = row;
return true;
}
else
{
return false;
}
}
public BufferedImage get(int col, int row)
{
if(col >= 0 || row >= 0)
{
return board[col][row];
}
else
{
return null;
}
}
public void randomize()
{
java.util.Random r = new java.util.Random();
for (int x = 0; x <= 10; x++)
{
go(r.nextInt(NUM_COLUMNS),r.nextInt(NUM_ROWS));
}
}
boolean complete()
{
boolean current = true;
for (int i = 0; i < NUM_COLUMNS; i++)
{
for (int j = 0; j < NUM_ROWS; j++)
{
if (control[i][j] != ((i * NUM_ROWS)+j))
{
current = false;
}
}
}
return current;
}
}
```