C Pocket Reference

Mathematical Functions for Real Floating Types

The mathematical functions declared in math.h were originally defined only for double values, with return values and parameters of type double. These functions are shown in Table 1-30.

Table 1-30. The traditional mathematical functions for double values

Mathematical function	C function
Trigonometric functions: Sine, cosine, tangent Arcsine, arccosine Arctangent	sin(), cos(), tan() asin(), acos() atan(), atan2()
Hyperbolic functions	sinh(), cosh(), tanh()
Powers, square root	pow(), sqrt(),
Exponential functions	exp(), frexp(), ldexp()
Logarithms	log(), log10()
Next integer	ceil(), floor()
Absolute value	fabs()
Remainder (modular division)	fmod()
Separation of integer and fractional parts	modf()

ANSI C99 introduces new versions of the functions listed in Table 1-30 for the types float and long double. The names of these functions end with f or l; for example:

double cos( double x );
float cosf( float x );
long double cosl( long double x );

New standard mathematical functions for real numbers have also been added in math.h , as listed in Table 1-31. These functions also have versions for float and long double, with names ending in f and l.

Table 1-31. New mathematical functions for double values in ANSI C99

Mathematical function	C function
Trigonometric functions	asinh(), acosh(), atanh()
Exponential functions	exp2(), expm1()
Logarithms	ilogb(), logb(), log1p(), log2()
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