Mathematical Functions
The standard library provides many mathematical functions. Most of them operate on real or complex floating-point numbers. However, there are also several functions with integer types, such as the functions to generate random numbers.
Mathematical Functions for Integer Types
The math functions for the integer types are declared in the header stdlib.h. Two of these functions, abs( ) and div( ), are declared in three variants to operate on the three signed integer types int, long, and long long. As following table shows, the functions for the type long have names beginning with the letter l; those for long long with ll. Furthermore, the header inttypes.h declares function variants for the type intmax_t, with names that begin with imax.
| Purpose | Functions declared in stdlib.h | Functions declared in stdint.h |
|---|---|---|
| Absolute value | abs( ), labs( ), llabs( ) | imaxabs( ) |
| Division | div( ), ldiv( ), lldiv( ) | imaxdiv( ) |
| Random numbers | rand( ), srand( ) |
Functions for real and complex floating-point types
| Mathematical function | C functions in math.h | C functions in complex.h |
|---|---|---|
| Trigonometry | sin( ), cos( ), tan( ), asin( ), acos( ), atan( ) | csin( ), ccos( ), ctan( ) casin( ), cacos( ), catan( ) |
| Hyperbolic trigonometry | sinh( ), cosh( ), tanh( ), asinh( ), acosh( ), atanh( ) |
csinh( ), ccosh( ), ctanh( ), casinh( ), cacosh( ), catanh( ) |
| Exponential function | exp( ) | cexp( ) |
| Natural logarithm | log( ) | clog( ) |
| Powers, square root | pow( ), sqrt( ) | cpow( ), csqrt( ) |
| Absolute value | fabs( ) | cabs( ) |
Functions for real floating-point types
| Mathematical function | C function |
|---|---|
| Arctangent of a quotient | atan2( ) |
| Exponential functions | exp2( ), expm1( ), frexp( ), ldexp( ), scalbn( ), scalbln( ) |
| Logarithmic functions | log10( ), log2( ), log1p( ), logb( ), ilogb( ) |
| Roots | cbrt( ), hypot( ) |
| Error functions for normal distributions | erf( ), erfc( ) |
| Gamma function | tgamma( ), lgamma( ) |
| Remainder | fmod( ), remainder( ), remquo( ) |
| Separate integer and fractional parts | modf( ) |
| Next integer | ceil( ), floor( ) |
| Next representable number | nextafter( ), nexttoward( ) |
| Rounding functions | trunc( ), round( ), lround( ), llround( ), nearbyint( ), rint( ), lrint( ), llrint( ) |
| Positive difference | fdim( ) |
| Multiply and add | fma( ) |
| Minimum and maximum | fmin( ), fmax( ) |
| Assign one number’s sign to another | copysign( ) |
| Generate a NaN | nan( ) |
Functions for complex floating-point types
| Mathematical function | C function |
|---|---|
| Isolate real and imaginary parts | creal( ), cimag( ) |
| Argument (the angle in polar coordinates) | carg( ) |
| Conjugate | conj( ) |
| Project onto the Riemann sphere | cproj( ) |
