Remember the best so far

You're looking through apartment listings for the biggest balcony. You don't write them all down: you just remember the biggest one you've seen so far, and swap it out whenever a bigger one turns up.

A loop can carry a value along in the same way. Keep one variable for "the biggest so far". At every box, compare: if this value is bigger, it becomes the new biggest. When the loop ends, it holds the answer.

Carry one value along: update it only when you beat it.

Keep the biggest so far

best starts at 3.

Move 1 of 5

Start with a real value, not 0

What should "the biggest so far" be before you've looked at anything? Starting at 0 feels natural, but try it on −5, −2, −9. No value beats 0, so you'd return 0, a number that isn't even in the list.

Start with the first box instead. It's always a real value, and until you've seen more, it really is the biggest.

Starting at 0: breaks when every number is negative.

Start with the first box: it's always a real value.

In code

best = nums[0]
for x in nums:
    if x > best:
        best = x
return best