div, ldiv, lldiv, imaxdiv

 

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Common mathematical functions

Functions
Basic operations
abslabsllabsimaxabs (C99) fabs divldivlldivimaxdiv (C99) fmod	remainder (C99) remquo (C99) fma (C99) fmax (C99) fmin (C99) fdim (C99) nannanfnanl (C99)(C99)(C99)
Exponential functions
exp exp2 (C99) expm1 (C99)	log log10 log1p (C99) log2 (C99)
Power functions
sqrt cbrt (C99)	hypot (C99) pow
Trigonometric and hyperbolic functions
sin cos tan asin acos atan atan2	sinh cosh tanh asinh (C99) acosh (C99) atanh (C99)
Error and gamma functions
erf (C99) erfc (C99)	lgamma (C99) tgamma (C99)
Nearest integer floating point operations
ceil floor roundlroundllround (C99)(C99)(C99)	trunc (C99) nearbyint (C99) rintlrintllrint (C99)(C99)(C99)
Floating point manipulation functions
ldexp scalbnscalbln (C99)(C99) ilogb (C99) logb (C99)	frexp modf nextafternexttoward (C99)(C99) copysign (C99)
Classification
fpclassify (C99)
isfinite (C99)
isinf (C99)
isnan (C99)
isnormal (C99)
signbit (C99)
Macro constants
HUGE_VALFHUGE_VALHUGE_VALL (C99)(C99)	FP_NORMALFP_SUBNORMALFP_ZEROFP_INFINITEFP_NAN (C99)(C99)(C99)(C99)(C99)

 

Defined in header <stdlib.h>
div_t     div( int x, int y );	(1)
ldiv_t    ldiv( long x, long y );	(2)
lldiv_t   lldiv( long long x, long long y );	(3)	(since C99)
Defined in header <inttypes.h>
imaxdiv_t imaxdiv( intmax_t x, intmax_t y );	(4)	(since C99)

Computes both the quotient and the remainder of the division of the numerator x by the denominator y

Computes quotient and remainder simultaneously. The quotient is the algebraic quotient with any fractional part discarded (truncated towards zero). The remainder is such that quot * y + rem == x.	(until C99)
Computes the quotient (the result of the expression x/y) and remainder (the result of the expression x%y) simultaneously.	(since C99)

Parameters

x, y

-

integer values

Return value

If both the remainder and the quotient can be represented as objects of the corresponding type (int, long, long long, imaxdiv_t, respectively), returns both as an object of type div_t, ldiv_t, ldiv_t, imaxdiv_t defined as follows:

div_t

struct div_t { int quot; int rem; };

or

struct div_t { int rem; int quot; };

ldiv_t

struct ldiv_t { long quot; long rem; };

or

struct ldiv_t { long rem; long quot; };

lldiv_t

struct lldiv_t { long long quot; long long rem; };

or

struct lldiv_t { long long rem; long long quot; };

imaxdiv_t

struct imaxdiv_t { intmax_t quot; intmax_t rem; };

or

struct imaxdiv_t { intmax_t rem; intmax_t quot; };

If either the remainder or the quotient cannot be represented, the behavior is undefined.

Notes

Until C99, the rounding direction of the quotient and the sign of the remainder in the built-in division and remainder operators was implementation-defined if either of the operands was negative, but it was well-defined in div and ldiv.

On many platforms, a single CPU instruction obtains both the quotient and the remainder, and this function may leverage that, although compilers are generally able to merge nearby / and % where suitable.

Example

Run this code

#include <stdio.h>
#include <math.h>
#include <stdlib.h>
 
// demo only: does not check for buffer overflow
void itoa(int n, int base, char* buf)
{
    div_t dv = {.quot = n};
    char* p = buf;
    do {
        dv = div(dv.quot, base);
        *p++ = "0123456789abcdef"[abs(dv.rem)];
    } while(dv.quot);
    if(n<0) *p++ = '-';
    *p-- = '\0';
    while(buf < p) { char c = *p; *p-- = *buf; *buf++ = c; } // reverse
}
 
int main(void)
{
    char buf[100];
    itoa(12346, 10, buf);
    printf("%s\n", buf);
    itoa(-12346, 10, buf);
    printf("%s\n", buf);
    itoa(65535, 16, buf);
    printf("%s\n", buf);
}

Output:

12346
-12346
ffff

See also

fmodfmodffmodl (C99)(C99)	computes remainder of the floating-point division operation (function)
remainderremainderfremainderl (C99)(C99)(C99)	computes signed remainder of the floating-point division operation (function)
remquoremquofremquol (C99)(C99)(C99)	computes signed remainder as well as the three last bits of the division operation (function)
C++ documentation for div