signed and unsigned integer
[1]
Variables such as integers can be represent in two ways, i.e., signed and
unsigned. Signed numbers use sign flag or can be distinguish between negative
values and positive values. Whereas unsigned numbers stored only positive
numbers but not negative numbers.
[2]
int and unsigned int are two distinct integer types. (int can also be referred
to as signed int, or just signed; unsigned int can also be referred to as
unsigned.)
As the names imply, int is a signed integer type, and unsigned int is an u
nsigned integer type. That means that int is able to represent negative values,
and unsigned int can represent only non-negative values.