function f = repVline(x,y,t);

% draws a vertical line of type t at each x-coord in x 
% from (largest value of the vector y + 0.5) to (smallest
% value of y - 0.5) 

hold on;
for j = 1:length(x) ;
  z = plot([x(j),x(j)],[min(y)-1,max(y)+1],t) ;
end;
hold off;
  
