std::nextafter, std::nexttoward

 

C++

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Common mathematical functions

Functions
Basic operations
abs(int)labsllabsimaxabs (C++11) abs(float)fabs divldivlldivimaxdiv (C++11) fmod	remainder (C++11) remquo (C++11) fma (C++11) fmax (C++11) fmin (C++11) fdim (C++11) nannanfnanl (C++11)(C++11)(C++11)
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sqrt cbrt (C++11)	hypot (C++11) pow
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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)
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ceil floor roundlroundllround (C++11)(C++11)(C++11)	trunc (C++11) nearbyint (C++11) rintlrintllrint (C++11)(C++11)(C++11)
Floating point manipulation functions
ldexp scalbnscalbln (C++11)(C++11) ilogb (C++11) logb (C++11)	frexp modf nextafternexttoward (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_VALFHUGE_VALHUGE_VALL (C++11)(C++11) INFINITY (C++11) NAN (C++11) math_errhandlingMATH_ERRNOMATH_ERREXCEPT (C++11)	FP_NORMALFP_SUBNORMALFP_ZEROFP_INFINITEFP_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