Sams Teach Yourself C in 21 Days

Exploring the C Function Library 535

19

log10() double log10(double x) Returns the base-10 logarithm of its argu-

ment. The argument must be greater than

0.

frexp() double frexp(double x, The function calculates the normalized

int *y) fraction representing the value x. The

function’s return value ris a fraction in

the range 0.5 <= r <= 1.0. The func-

tion assigns to yan integer exponent such

thatx = r * 2y. If the value passed to

the function is 0 , bothrandyare 0.

ldexp() double ldexp(double x, Returnsx * 2y.

int y)

Hyperbolic Functions ....................................................................................

The hyperbolic functions perform hyperbolic trigonometric calculations.

Function Prototype Description

cosh() double cosh(double x) Returns the hyperbolic cosine of its

argument.

sinh() double sinh(double x) Returns the hyperbolic sine of its

argument.

tanh() double tanh(double x) Returns the hyperbolic tangent of its

argument.

Other Mathematical Functions ......................................................................

The standard C library contains the following miscellaneous mathematical functions:

Function Prototype Description

sqrt() double sqrt(double x) Returns the square root of its argu-

ment. The argument must be zero or

greater.

ceil() double ceil(double x) Returns the smallest integer not less

than its argument. For example,

ceil(4.5)returns5.0, andceil(-

4.5)returns-4.0. Although ceil()

returns an integer value, it is returned

as a type double.

Function Prototype Description

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