C has several shorthand tricks you can use to make your life easier. For instance, it is very common inside a loop to have a counter you want to increment (add 1) or decrement (subtract 1) on each pass. C lets you do this by using a double symbol such as:

int a = 1;
a++;

This would now set the value in a to be 2. The shorthand for decrementing is -- instead of ++. So if we wanted to decrement a, it would be:

a--;