This chapter contains information about functions for performing mathematical computations, such as trigonometric functions. Most of these functions have prototypes declared in the header file `math.h'. The complex-valued functions are defined in `complex.h'.
All mathematical functions which take a floating-point argument
have three variants, one each for double
, float
, and
long double
arguments. The double
versions are mostly
defined in ISO C89. The float
and long double
versions are from the numeric extensions to C included in ISO C99.
Which of the three versions of a function should be used depends on the
situation. For most calculations, the float
functions are the
fastest. On the other hand, the long double
functions have the
highest precision. double
is somewhere in between. It is
usually wise to pick the narrowest type that can accommodate your data.
Not all machines have a distinct long double
type; it may be the
same as double
.
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