There
are only a few basic data types in C:
char a
single byte, capable of holding one character in the local character set int an
integer, typically reflecting the natural size of integers on the host machine float single-precision floating point
double double-precision floating point
In addition,
there are a number of qualifiers that can be applied to these basic types. short and long apply to integers:
short int sh; long int counter;
The word int can be omitted in such declarations,
and typically it is.
The
intent is that short
and long should provide different lengths of
integers where practical; int will
normally be the natural size for a particular machine. short is often 16 bits long, and int either 16 or 32 bits. Each compiler
is free to choose appropriate sizes for its own hardware, subject only to the
the restriction that shorts
and ints are at least 16 bits, longs are at least 32 bits, and short is no longer than int, which is no longer than long.
The
qualifier signed or unsigned may be applied to char or any integer. unsigned numbers are always positive or zero,
and obey the laws of arithmetic modulo 2n,
where n is the number of bits in the
type. So, for instance, if chars are 8 bits, unsigned char variables have values between 0 and
255, while signed
chars have values
between -128 and 127 (in a two's complement machine.) Whether plain chars are signed or unsigned is
machine-dependent, but printable characters are always positive.
The
type long
double specifies
extended-precision floating point. As with integers, the sizes of
floating-point objects are implementation-defined; float, double and long double could represent one, two or three
distinct sizes.
The
standard headers
Revison . Write a program to determine the ranges of char, short, int, and long variables, both signed and unsigned, by printing appropriate values
from standard headers and by direct computation. Harder if you compute them:
determine the ranges of the various floating-point types.
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