public String toString(){
		int i;
		String tmp = "";
		tmp += this.clr==ChessBoard.RED?"RED":"BLUE";
		switch(this.direction){
		case Chessline.LEFT:
			for(i=this.chess_num-1;i>=0;i--){
				tmp+="("+(this.start_x-i)+","+this.start_y+")";
			}
			break;
			
		case Chessline.DOWN:
			for(i=this.chess_num-1;i>=0;i--)
			{
				tmp+="("+this.start_x+","+(this.start_y-i)+")";
			}
			break;
		case Chessline.DOWNLEFT:
			for(i=this.chess_num-1;i>=0;i--)
			{
				tmp+="("+(this.start_x-i)+","+(this.start_y-i)+")";
			}
			break;
		
		case Chessline.DOWNRIGHT:
			for(i=this.chess_num-1;i>=0;i--)
			{
				tmp+="("+(this.start_x+i)+","+(this.start_y-i)+")";
			}
			break;
			
			default:
				throw new java.lang.RuntimeException("The direction is illegal!");
		}
		
		return tmp;
	}