如何测试二维网格上的位置是否包含数组中的对象？

Question

I was making a game where there is a 2d grid with walls, players, and enemies. I have a file with the 2d grid with each as a different character. While reading the file, I assigned a 2d array to contain the values of the walls as they will not move, but I created a new enemy and new player when the character for either was read. Now I'm trying to display the players and enemies and I cannot figure out how to. Here's my code:

private char[][] cells;
private Player player;
private Lion[] lions;

public boolean hasPlayer(int row, int col)
{
    return false;       // needs fixing
}

public boolean hasLion(int row, int col)
{
if(cells[row][col] == '&') return true;
    else return false;      // needs fixing
}

public void display{
for(int i = 0; i < ROWS; i++)  
{
  for(int j = 0; j < COLS; j++) 
  {
    if(hasPlayer(i,j)){
      System.out.print(Main.BLUE + "P ");
    }
            
    else if(hasLion(i,j)){
      System.out.print(Main.YELLOW + "& ");
    }
   }
  }    
 }

Answer 1

You haven't shared the definition of your Lion and Player classes...

I'm assuming that they will each have getRow() and getCol() methods, and that your cells array only contains the walls and no player or lion characters.

public boolean hasPlayer(int row, int col)
{
    return (this.player.getRow() == row && this.player.getCol() == col);
}

public boolean hasLion(int row, int col)
{
    return this.lions.stream().anyMatch(lion -> lion.getRow() == row && lion.getCol() == col)
}

adding a boolean isAt(int col, int row) method to your Lion and Player classes would make this code tidier.

you may also need to print cells[i][j] every time nothing is matched, and a new line after each row.