Integers come in two varieties: signed and unsigned. The idea here is that sometimes you need negative numbers, and sometimes you don't. Integers (short and long) that aren't labeled unsigned are assumed to be signed. signed integers are either negative or positive. unsigned integers are always positive.
Use int for Number Variables
For most programs, most of the time, you can simply declare your simple number variables as ints—these are signed integers.
Several variable types are built into C++. They can be conveniently divided into integer variables (the type discussed so far), character ...