Signedness
In computing,
signedness is a property of variables representing
numbers in computer programs. A numeric variable is
signed if it can represent both
positive and negative numbers, and
unsigned if it can only represent positive numbers.
Although this distinction is often made in computer s, which require it to do
arithmetic correctly, it is concealed by many
programming languages. Generally, only languages which stay close to hardware's constraints (so-called "low-level" languages) require programmers to make the distinction. These include
assembly language,
C and
C++.
While
signed numbers can represent negative numbers they lose a range of larger numbers which can only be represented with
unsigned numbers of the same size (in bits).This is because in signed variables, one bit is used to indicate signedness, dividing the number of positive values that can be represented by two. Unsigned variables can dedicate all their bits to the positive number range.
*
Sign bit*
Two's complement*
Signed number representations
