std::nextafter, std::nexttoward

 

C++

Language

Standard library headers

Concepts

Utilities library

Strings library

Containers library

Algorithms library

Iterators library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

 

Numerics library

Common mathematical functions

Floating-point environment

Complex numbers

Numeric arrays

Pseudo-random number generation

Compile-time rational arithmetic (C++11)

Generic numeric operations

iota (C++11)

accumulate

inner_product

adjacent_difference

partial_sum

 

Common mathematical functions

Functions
Basic operations
abs(int) labs llabs imaxabs (C++11) abs(float) fabs div ldiv lldiv imaxdiv (C++11) fmod	remainder (C++11) remquo (C++11) fma (C++11) fmax (C++11) fmin (C++11) fdim (C++11) nan nanf nanl (C++11) (C++11) (C++11)
Exponential functions
exp exp2 (C++11) expm1 (C++11)	log log10 log1p (C++11) log2 (C++11)
Power functions
sqrt cbrt (C++11)	hypot (C++11) pow
Trigonometric and hyperbolic functions
sin cos tan asin acos atan atan2	sinh cosh tanh asinh (C++11) acosh (C++11) atanh (C++11)

Error and gamma functions
erf (C++11) erfc (C++11)	lgamma (C++11) tgamma (C++11)
Nearest integer floating point operations
ceil floor round lround llround (C++11) (C++11) (C++11)	trunc (C++11) nearbyint (C++11) rint lrint llrint (C++11) (C++11) (C++11)
Floating point manipulation functions
ldexp scalbn scalbln (C++11) (C++11) ilogb (C++11) logb (C++11)	frexp modf nextafter nexttoward (C++11) (C++11) copysign (C++11)
Classification/Comparison
fpclassify (C++11) isfinite (C++11) isinf (C++11) isnan (C++11) isnormal (C++11) signbit (C++11)	isgreater (C++11) isgreaterequal (C++11) isless (C++11) islessequal (C++11) islessgreater (C++11) isunordered (C++11)
Macro constants
HUGE_VALF HUGE_VAL HUGE_VALL (C++11) (C++11) INFINITY (C++11) NAN (C++11) math_errhandling MATH_ERRNO MATH_ERREXCEPT (C++11)	FP_NORMAL FP_SUBNORMAL FP_ZERO FP_INFINITE FP_NAN (C++11) (C++11) (C++11) (C++11) (C++11)

 

Defined in header <cmath>
float       nextafter( float from, float to );	(1)	(since C++11)
double      nextafter( double from, double to );	(2)	(since C++11)
long double nextafter( long double from, long double to );	(3)	(since C++11)
Promoted    nextafter( Arithmetic from, Arithmetic to );	(4)	(since C++11)
float       nexttoward( float from, long double to );	(5)	(since C++11)
double      nexttoward( double from, long double to );	(6)	(since C++11)
long double nexttoward( long double from, long double to );	(7)	(since C++11)
double      nexttoward( Integral from, long double to );	(8)	(since C++11)

Returns the next representable value of from in the direction of to. If from equals to to, to is returned.

4) If any argument has integral type, it is cast to double. If any other argument is long double, then the return type is long double, otherwise it is double

Parameters

from, to

-

floating point values

Return value

the next representable value of from in the direction of to.

Example

run this code

#include <cmath>
#include <iostream>
#include <iomanip>
 
int main()
{
    std::cout << "0.1 lies between the doubles " << std::setprecision(100) << '\n'
              << 0.1 << '\n' << " and\n"
              << std::nextafter(0.1, 0) << '\n';
}

Output:

0.1 lies between the doubles 
0.1000000000000000055511151231257827021181583404541015625
 and
0.09999999999999999167332731531132594682276248931884765625