重写equals和toString

public class Cell {

public int x;

public int y;

public Cell(int x, int y){

this.x = x;

this.y =y;

}

public String toString(){

return +x+","+y;

}

public boolean equals(Object obj){

if(this == obj){

return true;

}

if(obj == null){

return false;

}

if(obj instanceof Cell){

Cell c = (Cell) obj;

return this.x == c.x && this.y == c.y;

}else{

return false;

}

}