function plotfoil()
% This is a simple matlab plotting function for use with the 
% airfoil data files obtained from the
% University of Illinois at Urbana-Champaign
%
% usage:
% just type plotfoil, and select a file in the pop-up dialog
%
ok = 1;
while (ok)
    [dfile,dpath] = uigetfile('*.*',...
                            'Airfoil Data File Name',...
                             100,100);
    if (~(dfile == 0))
       fid = fopen([dpath,dfile],'r');

       name         = fgetl(fid);
       [pts,count]  = fscanf(fid,'%f');

       if ( (pts(1) == floor(pts(1))) & (pts(1)>5) )
            % "Lednicers" format
            npts_top = pts(1);
            npts_bot = pts(2);

            top = zeros(2,npts_top);
            bot = zeros(2,npts_bot);
            
            tp = pts(3:2+2*npts_top);
            bt = pts(3+2*npts_top:2+2*npts_top+2*npts_bot);
            
            top(:) = tp;
            bot(:) = bt;

            figure;
            set(gcf,'name',name);
            plot(top(1,:),top(2,:),'w');
            hold on
            plot(bot(1,:),bot(2,:),'w');
            axis([0 1 -.5 .5]);
            title(name);
       elseif (length(pts)/2 == floor(length(pts)/2))
            % "selig"  format assumed...
            npts = length(pts)/2;
            foil = zeros(2,npts);
            foil(:) = pts;
            figure;
            set(gcf,'name',name);
            plot(foil(1,:),foil(2,:),'w');
            axis([0 1 -.5 .5]);
            title(name);
       else    % n x y format assumed
            npts = length(pts)/3;
            if (npts ~= floor(npts))
               error('unrecognized file format');
            end 
            foil = zeros(3,npts);
            foil(:) = pts;
            figure;
            set(gcf,'name',name);
            plot(foil(2,:),foil(3,:),'w');
            axis([0 1 -.5 .5]);
            title(name);
       end
    else
       ok = 0;
    end
end