how to find every minimum and maximum values of a graph?

I did a graph on Matlab and I'm trying to locate every Minimum and maximum on the graph. This is the graph code What is the code to find every minimum and maximum values in this graph?

x = linspace (-6,6);

y = (x+6) .* (x+4) .* (x+2) .* (x) .* (x-2) .* (x-4) .* (x-6) ;

[Image Analyst]

http://www.mathworks.com/matlabcentral/answers/13205-tutorial-how-to-format-your-question-with-markup

Answer 1

[Matt J]

ymax=max(y);

xmax=find(y==ymax);

xmin=find(y==min(y));