How to select the x-value of the maximum of a figure (without using ginput)?

I've got a figure (see attachment). I want to select the x-value of it's maximum. How do I do this?

Answer 1

[Star Strider]

I would use the max function with two output arguments, then use the index value to find the x-value:

[ymax,idx] = max(y);
xmax = x(idx);

Answer 2

[Sean de Wolski]

You could use datacursortmode the axes 'ButtonDownFcn' or max() on the line's 'YData'. This is what I would do.

plot(rand(1,10));
hLine = findobj(gca,'type','line');
[~,idx] = max(hLine.YData)
hLine.XData(idx)