Defined in header <cmath> | ||
---|---|---|
float remainder ( float x, float y ); float remainderf( float x, float y ); | (1) | (since C++11) |
double remainder ( double x, double y ); | (2) | (since C++11) |
long double remainder ( long double x, long double y ); long double remainderl( long double x, long double y ); | (3) | (since C++11) |
Promoted remainder ( Arithmetic1 x, Arithmetic2 y ); | (4) | (since C++11) |
x/y
.double
. If any other argument is long double
, then the return type is long double
, otherwise it is double
.The IEEE floating-point remainder of the division operation x/y
calculated by this function is exactly the value x - n*y
, where the value n
is the integral value nearest the exact value x/y
. When |n-x/y| = ½, the value n
is chosen to be even.
In contrast to std::fmod()
, the returned value is not guaranteed to have the same sign as x
.
If the returned value is 0
, it will have the same sign as x
.
x, y | - | values of floating-point or integral types |
If successful, returns the IEEE floating-point remainder of the division x/y
as defined above.
If a domain error occurs, an implementation-defined value is returned (NaN where supported).
If a range error occurs due to underflow, the correct result is returned.
If y
is zero, but the domain error does not occur, zero is returned.
Errors are reported as specified in math_errhandling
.
Domain error may occur if y
is zero.
If the implementation supports IEEE floating-point arithmetic (IEC 60559),
FE_INEXACT
is never raised, the result is always exact. x
is ±∞ and y
is not NaN, NaN is returned and FE_INVALID
is raised y
is ±0 and x
is not NaN, NaN is returned and FE_INVALID
is raised POSIX requires that a domain error occurs if x
is infinite or y
is zero.
std::fmod
, but not std::remainder
is useful for doing silent wrapping of floating-point types to unsigned integer types: (0.0 <= (y = std::fmod( std::rint(x), 65536.0 )) ? y : 65536.0 + y)
is in the range [-0.0 .. 65535.0]
, which corresponds to unsigned short
, but std::remainder(std::rint(x), 65536.0)
is in the range [-32767.0, +32768.0]
, which is outside of the range of signed short
.
#include <iostream> #include <cmath> #include <cfenv> #pragma STDC FENV_ACCESS ON int main() { std::cout << "remainder(+5.1, +3.0) = " << std::remainder(5.1,3) << '\n' << "remainder(-5.1, +3.0) = " << std::remainder(-5.1,3) << '\n' << "remainder(+5.1, -3.0) = " << std::remainder(5.1,-3) << '\n' << "remainder(-5.1, -3.0) = " << std::remainder(-5.1,-3) << '\n'; // special values std::cout << "remainder(-0.0, 1.0) = " << std::remainder(-0.0, 1) << '\n' << "remainder(5.1, Inf) = " << std::remainder(5.1, INFINITY) << '\n'; // error handling std::feclearexcept(FE_ALL_EXCEPT); std::cout << "remainder(+5.1, 0) = " << std::remainder(5.1, 0) << '\n'; if(fetestexcept(FE_INVALID)) std::cout << " FE_INVALID raised\n"; }
Possible output:
remainder(+5.1, +3.0) = -0.9 remainder(-5.1, +3.0) = 0.9 remainder(+5.1, -3.0) = -0.9 remainder(-5.1, -3.0) = 0.9 remainder(-0.0, 1.0) = -0 remainder(5.1, Inf) = 5.1 remainder(+5.1, 0) = -nan FE_INVALID raised
(C++11) | computes quotient and remainder of integer division (function) |
(C++11)(C++11) | remainder of the floating point division operation (function) |
(C++11)(C++11)(C++11) | signed remainder as well as the three last bits of the division operation (function) |
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