div, ldiv, lldiv, imaxdiv
| Defined in header
<stdlib.h>
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||
| div_t div( int x, int y );
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(1) | |
| ldiv_t ldiv( long x, long y );
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(2) | |
| lldiv_t lldiv( long long x, long long y );
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(3) | (since C99) |
| Defined in header
<inttypes.h>
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||
| (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, imaxdiv_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 <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
[edit] References
- C11 standard (ISO/IEC 9899:2011):
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- 7.8.2.2 The imaxdiv function (p: 219)
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- 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)
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- 7.20.6.2 The div, ldiv and lldiv functions (p: 320)
- C89/C90 standard (ISO/IEC 9899:1990):
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- 4.10 div_t, ldiv_t
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- 4.10.6.2 The div function
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- 4.10.6.4 The ldiv function
[edit] See also
| (C99)(C99)
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computes remainder of the floating-point division operation (function) |
| (C99)(C99)(C99)
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computes signed remainder of the floating-point division operation (function) |
| (C99)(C99)(C99)
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computes signed remainder as well as the three last bits of the division operation (function) |
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C++ documentation for div
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