Defined in header
floatremainder(floatx,floaty);doubleremainder(doublex,doubley);longdoubleremainder(longdoublex,longdoubley); (1)(until C++23)constexpr/*floating-point-type*/remainder(/*floating-point-type*/x,/*floating-point-type*/y);(since C++23)floatremainderf(floatx,floaty); (2)(since C++11)
(constexpr since C++23)longdoubleremainderl(longdoublex,longdoubley); (3)(since C++11)
(constexpr since C++23)
(since C++26)
Defined in header
template<classV0,classV1>constexpr/*math-common-simd-t*/<V0,V1>remainder(constV0&v_x,constV1&v_y); (S) (since C++26)
(since C++11)
Defined in header
template<classInteger>doubleremainder(Integerx,Integery); (A)(constexpr since C++23)1-3) Computes the IEEE remainder of the floating point division operation x/y. The library provides overloads of std::remainder for all cv-unqualified floating-point types as the type of the parameters.(since C++23)
S) The SIMD overload performs an element-wise std::remainder on v_xand v_y.
(See
for its definition.)(since C++26)A) Additional overloads are provided for all integer types, which are treated as double.
(since C++11)The IEEE floating-point remainder of the division operation x/y calculated by this function is exactly the value x-quo*y, where the value quo is the integral value nearest the exact value x/y. When |quo - x / y| = ½, the value quo is chosen to be even.
In contrast to
, the returned value is not guaranteed to have the same sign as x.
If the returned value is zero, it will have the same sign as x.
Parameters
x, y - floating-point or integer values Return value
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.
Error handling
Errors are reported as specified in
.
Domain error may occur if y is zero.
If the implementation supports IEEE floating-point arithmetic (IEC 60559),
The current
has no effect.
is never raised, the result is always exact.
If x is ±∞ and y is not NaN, NaN is returned and
is raised.
If y is ±0 and x is not NaN, NaN is returned and
is raised.
If either argument is NaN, NaN is returned.
Notes
that a domain error occurs if x is infinite or y is zero.
, 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 unsignedshort, but std::remainder(std::rint(x),65536.0) is in the range [-32767.0, +32768.0], which is outside of the range of signedshort.
The additional overloads are not required to be provided exactly as (A). They only need to be sufficient to ensure that for their first argument num1 and second argument num2:
If num1 or num2 has type longdouble, then std::remainder(num1,num2) has the same effect as std::remainder(static_cast<longdouble>(num1),
static_cast<longdouble>(num2)).
Otherwise, if num1 and/or num2 has type double or an integer type, then std::remainder(num1,num2) has the same effect as std::remainder(static_cast<double>(num1),
static_cast<double>(num2)).
Otherwise, if num1 or num2 has type float, then std::remainder(num1,num2) has the same effect as std::remainder(static_cast<float>(num1),
static_cast<float>(num2)).
(until C++23)If num1 and num2 have arithmetic types, then std::remainder(num1,num2) has the same effect as std::remainder(static_cast</*common-floating-point-type*/>(num1),
static_cast</*common-floating-point-type*/>(num2)), where /*common-floating-point-type*/ is the floating-point type with the greatest
floating-point conversion rank
and greatest
floating-point conversion subrank
between the types of num1 and num2, arguments of integer type are considered to have the same floating-point conversion rank as double.
If no such floating-point type with the greatest rank and subrank exists, then
does not result in a usable candidate from the overloads provided.
(since C++23)Example
Run this code
#include<cfenv>#include<cmath>#include<iostream>// #pragma STDC FENV_ACCESS ONintmain(){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 valuesstd::cout<<"remainder(-0.0, 1.0) = "<<std::remainder(-0.0,1)<<'\n'<<"remainder(5.1, Inf) = "<<std::remainder(5.1,INFINITY)<<'\n';// error handlingstd::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 See also