You can use a comma in other expressions to introduce a sequence point: http://c-faq.com/~scs/cgi-bin/faqcat.cgi?sec=expr#seqpoints
You surely are right. I wanted to give a quick example, turns out it was a bad one. Next time I'll write :
int i = 0;
printf("%i", i++); // prints 0
printf("%i", ++i); // prints 2
Given that you were making a point on an article about the complexity of C, I'd say it was an unintentionally excellent example.
i = i++;