<s>
In	O
computing	O
,	O
signedness	B-Algorithm
is	O
a	O
property	O
of	O
data	O
types	O
representing	O
numbers	O
in	O
computer	O
programs	O
.	O
</s>
<s>
A	O
numeric	O
variable	O
is	O
signed	O
if	O
it	O
can	O
represent	O
both	O
positive	O
and	O
negative	O
numbers	O
,	O
and	O
unsigned	B-Algorithm
if	O
it	O
can	O
only	O
represent	O
non-negative	O
numbers	O
(	O
zero	O
or	O
positive	O
numbers	O
)	O
.	O
</s>
<s>
As	O
signed	O
numbers	O
can	O
represent	O
negative	O
numbers	O
,	O
they	O
lose	O
a	O
range	O
of	O
positive	O
numbers	O
that	O
can	O
only	O
be	O
represented	O
with	O
unsigned	B-Algorithm
numbers	I-Algorithm
of	O
the	O
same	O
size	O
(	O
in	O
bits	O
)	O
because	O
roughly	O
half	O
the	O
possible	O
values	O
are	O
non-positive	O
values	O
,	O
whereas	O
the	O
respective	O
unsigned	B-Algorithm
type	O
can	O
dedicate	O
all	O
the	O
possible	O
values	O
to	O
the	O
positive	O
number	O
range	O
.	O
</s>
<s>
For	O
example	O
,	O
a	O
two	B-General_Concept
's	I-General_Concept
complement	I-General_Concept
signed	O
16-bit	O
integer	O
can	O
hold	O
the	O
values	O
−32768	O
to	O
32767	O
inclusively	O
,	O
while	O
an	O
unsigned	B-Algorithm
16	O
bit	O
integer	O
can	O
hold	O
the	O
values	O
0	O
to	O
65535	O
.	O
</s>
<s>
For	O
this	O
sign	B-Algorithm
representation	I-Algorithm
method	O
,	O
the	O
leftmost	O
bit	O
(	O
most	O
significant	O
bit	O
)	O
denotes	O
whether	O
the	O
value	O
is	O
negative	O
(	O
0	O
for	O
positive	O
or	O
zero	O
,	O
1	O
for	O
negative	O
)	O
.	O
</s>
<s>
For	O
most	O
architectures	O
,	O
there	O
is	O
no	O
signed	O
–	O
unsigned	B-Algorithm
type	O
distinction	O
in	O
the	O
machine	B-Language
language	I-Language
.	O
</s>
<s>
Nevertheless	O
,	O
arithmetic	O
instructions	O
usually	O
set	O
different	O
CPU	B-General_Concept
flags	I-General_Concept
such	O
as	O
the	O
carry	B-Algorithm
flag	I-Algorithm
for	O
unsigned	B-Algorithm
arithmetic	O
and	O
the	O
overflow	B-Algorithm
flag	I-Algorithm
for	O
signed	O
.	O
</s>
<s>
Those	O
values	O
can	O
be	O
taken	O
into	O
account	O
by	O
subsequent	O
branch	B-General_Concept
or	O
arithmetic	O
commands	O
.	O
</s>
<s>
The	O
C	B-Language
programming	I-Language
language	I-Language
,	O
along	O
with	O
its	O
derivatives	O
,	O
implements	O
a	O
signedness	B-Algorithm
for	O
all	O
integer	O
data	O
types	O
,	O
as	O
well	O
as	O
for	O
"	O
character	O
"	O
.	O
</s>
<s>
For	O
Integers	O
,	O
the	O
modifier	O
defines	O
the	O
type	O
to	O
be	O
unsigned	B-Algorithm
.	O
</s>
<s>
The	O
default	O
integer	O
signedness	B-Algorithm
is	O
signed	O
,	O
but	O
can	O
be	O
set	O
explicitly	O
with	O
modifier	O
.	O
</s>
<s>
By	O
contrast	O
,	O
the	O
C	B-Language
standard	O
declares	O
,	O
,	O
and	O
,	O
to	O
be	O
three	O
distinct	O
types	O
,	O
but	O
specifies	O
that	O
all	O
three	O
must	O
have	O
the	O
same	O
size	O
and	O
alignment	O
.	O
</s>
<s>
Integer	O
literals	O
can	O
be	O
made	O
unsigned	B-Algorithm
with	O
suffix	O
.	O
</s>
<s>
Compilers	O
often	O
issue	O
a	O
warning	O
when	O
comparisons	O
are	O
made	O
between	O
signed	O
and	O
unsigned	B-Algorithm
numbers	I-Algorithm
or	O
when	O
one	O
is	O
cast	O
to	O
the	O
other	O
.	O
</s>
<s>
These	O
are	O
potentially	O
dangerous	O
operations	O
as	O
the	O
ranges	O
of	O
the	O
signed	O
and	O
unsigned	B-Algorithm
types	O
are	O
different	O
.	O
</s>
