In a way it is a pity that that was your take home lesson. You deserved an A++ and the take home should have been that going the extra mile gets rewarded.
I did have a couple other classes that were a bit better -- Assembly (BAL on an IBM Mainframe), in which the instructor presented an award to me at the end of the semester, my very own pocket protector. And a C class I took, had a similar calculator project, so I ended up doing a parse tree with recursive evaluation in order to do handle operator precedence and parentheses. In that class, the instructor made handouts out of my homework assignment to go over as an example of good programming technique and an intro to algorithms for the rest of the class. Made me feel special at the time.
Yet, in CS courses it doesn't. An A+ means you passed all of the automated tests.