Counting down starts at a high value and decreases each iteration. You use i-- or i -= step to move backward through your range. Example: for (int i = 10; i >= 1; i--) counts 10 down to 1.
The condition i >= 1 includes 1 in the output because we check greater-than-or-equal. Counting down is useful for processing arrays in reverse order or generating countdowns. Make sure the condition uses >= or > instead of <= when decrementing.