Defined in header <math.h> | ||
---|---|---|
float remainderf( float x, float y ); | (1) | (since C99) |
double remainder( double x, double y ); | (2) | (since C99) |
long double remainderl( long double x, long double y ); | (3) | (since C99) |
Defined in header <tgmath.h> | ||
#define remainder( x, y ) | (4) | (since C99) |
x/y
.long double
, remainderl
is called. Otherwise, if any argument has integer type or has type double
, remainder
is called. Otherwise, remainderf
is called.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 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 | - | floating point values |
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.
fmod
, but not remainder
is useful for doing silent wrapping of floating-point types to unsigned integer types: (0.0 <= (y = fmod(rint(x), 65536.0)) ? y : 65536.0 + y)
is in the range [-0.0 .. 65535.0]
, which corresponds to unsigned short
, but remainder(rint(x), 65536.0)
is in the range [-32767.0, +32768.0]
, which is outside of the range of signed short
.
#include <stdio.h> #include <math.h> #include <fenv.h> #pragma STDC FENV_ACCESS ON int main(void) { printf("remainder(+5.1, +3.0) = %.1f\n", remainder(5.1,3)); printf("remainder(-5.1, +3.0) = %.1f\n", remainder(-5.1,3)); printf("remainder(+5.1, -3.0) = %.1f\n", remainder(5.1,-3)); printf("remainder(-5.1, -3.0) = %.1f\n", remainder(-5.1,-3)); // special values printf("remainder(-0.0, 1.0) = %.1f\n", remainder(-0.0, 1)); printf("remainder(+5.1, Inf) = %.1f\n", remainder(5.1, INFINITY)); // error handling feclearexcept(FE_ALL_EXCEPT); printf("remainder(+5.1, 0) = %.1f\n", remainder(5.1, 0)); if(fetestexcept(FE_INVALID)) puts(" FE_INVALID raised"); }
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) = 0.0 remainder(-0.0, 1.0) = -0.0 remainder(+5.1, Inf) = 5.1 remainder(+5.1, 0) = -nan FE_INVALID raised
(C99) | computes quotient and remainder of integer division (function) |
(C99)(C99) | computes remainder of the floating-point division operation (function) |
(C99)(C99)(C99) | computes signed remainder as well as the three last bits of the division operation (function) |
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