What do you use to test the speed of a piece of code/application?

that's it everyone, we can go home. the perfect solution has been performed.

What's a positive zero? Does that imply the existence of a negative zero?

To further clarify for those still confused on why passing in switch(value) doesn't work, it's because it's comparing a Boolean to a numerical one, which will always be false. Say our average is 95 and we're assigning that to a variable avg. If we try to pass in avg as the argument to the switch statement's parameter, this is essentially what is happening:

switch(avg) {              //avg == 95
   case (avg >= 90):         //comparing 95 to true, which is false
     return 'A';

(avg >= 90) is returning a Boolean. We'll never reach a switch statement that evaluates to true if we're passing in our avg variable as the argument. I hope this helps!

incredible