div, ldiv, lldiv, imaxdiv
| Defined in header <stdlib.h>
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| 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>
|
||
| (4) | (since C99) | |
Computes both the quotient and the remainder of the division of the numerator x by the denominator y.
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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) |
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Computes the quotient (the result of the expression x / y) and remainder (the result of the expression x % y) simultaneously. |
(since C99) |
Contents |
[edit] Parameters
| x, y | - | integer values |
[edit] Return value
If both the remainder and the quotient can be represented as objects of the corresponding type (int, long, long long, intmax_t, respectively), returns both as an object of type div_t, ldiv_t, lldiv_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
or
If either the remainder or the quotient cannot be represented, the behavior is undefined.
[edit] 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.
[edit] Example
#include <assert.h> #include <stdio.h> #include <math.h> #include <stdlib.h> #include <limits.h> void reverse(char* first, char* last) { for (--last; first < last; ++first, --last) { char c = *last; *last = *first; *first = c; } } // demo only: does not check for buffer overflow char* itoa(int n, int base, char* buf) { assert(2 <= base && base <= 16); 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'; reverse(buf, p); return buf; } int main(void) { char buf[100]; printf("%s\n", itoa(0, 2, buf)); printf("%s\n", itoa(007, 3, buf)); printf("%s\n", itoa(12346, 10, buf)); printf("%s\n", itoa(-12346, 10, buf)); printf("%s\n", itoa(-42, 2, buf)); printf("%s\n", itoa(INT_MAX, 16, buf)); printf("%s\n", itoa(INT_MIN, 16, buf)); }
Possible output:
0 21 12346 -12346 -101010 7fffffff -80000000
[edit] References
- C17 standard (ISO/IEC 9899:2018):
- 7.8.2.2 The imaxdiv function (p: 159)
- 7.22.6.2 The div, ldiv and lldiv functions (p: 259)
- C11 standard (ISO/IEC 9899:2011):
- 7.8.2.2 The imaxdiv function (p: 219)
- 7.22.6.2 The div, ldiv and lldiv functions (p: 356)
- C99 standard (ISO/IEC 9899:1999):
- 7.8.2.2 The imaxdiv function (p: 200)
- 7.20.6.2 The div, ldiv and lldiv functions (p: 320)
- C89/C90 standard (ISO/IEC 9899:1990):
- 4.10 div_t, ldiv_t
- 4.10.6.2 The div function
- 4.10.6.4 The ldiv function
[edit] See also
| (C99)(C99) |
computes remainder of the floating-point division operation (function) |
| (C99)(C99)(C99) |
computes signed 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) |
| C++ documentation for div
| |
[edit] External links
| Euclidean Division |
