Save graph / plot progressively

Good evening, i need help, i want that my code saves plot in progressive mode. I thought to use saveas function in a code like this

f = figure('Visible', 'off');
plot(x,y,'r');
saveas(f,'figure_',num2str(numberofgraph,'%d'),'.jpeg');

but it doesn't work, it says "too many imput arguments"(i think it doesn't like

num2str(numberofgraph,'%d'),

How can i also decide where it has to save it? Thanks for your help

Answer 1

[Walter Roberson]

saveas(f,['figure_',num2str(numberofgraph,'%d'),'.jpeg']);

Answer 2

[Nicola]

Thanks very much Mr Walter Roberson. Is 'savesas' the best function or there is one which gives me a better quality of images?

Thanks