Representing whole numbers
The basic whole number type is an integer or just int. Integers can either be positive only, called unsigned, or they can be negative and positive, called signed. As you might expect, the natural use for integers is to count things. You must specify unsigned if you know you will not require negative values.
To be explicit, the default type is signed int, where the signed keyword is optional.
An unsigned integer has 0 as its lowest value; its highest value is when all bits are set to 1. For instance, a single byte value has a possible 256 values, but their range is 0 to 255. This is sometimes called the one-off problem where the starting value for counting is 0 and not 1, as we were taught when we first learned to count. This is a problem because it takes some time for new programmers to adjust their thinking. Until you are comfortable about thinking in this way, the one-off problem will be a common source of confusion and possibly the cause of bugs...
