Defined in header `<cstdlib>` | ||
---|---|---|

std::div_t div( int x, int y ); | (1) | |

std::ldiv_t div( long x, long y ); | (2) | |

std::lldiv_t div( long long x, long long y ); | (3) | (since C++11) |

std::ldiv_t ldiv( long x, long y ); | (4) | |

std::lldiv_t lldiv( long long x, long long y ); | (5) | (since C++11) |

Defined in header `<cinttypes>` | ||

std::imaxdiv_t div( std::intmax_t x, std::intmax_t y ); | (6) | (since C++11) |

std::imaxdiv_t imaxdiv( std::intmax_t x, std::intmax_t y ); | (7) | (since C++11) |

Computes both the quotient and the remainder of the division of the numerator `x`

by the denominator `y`

.

The quotient is the algebraic quotient with any fractional part discarded (truncated towards zero). The remainder is such that | (until C++11) |

The quotient is the result of the expression | (since C++11) |

x, y | - | integer values |

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

, `std::ldiv_t`

, `std::lldiv_t`

, `std::imaxdiv_t`

defined as follows:

struct div_t { int quot; int rem; };

or.

struct div_t { int rem; int quot; };

struct ldiv_t { long quot; long rem; };

or.

struct ldiv_t { long rem; long quot; };

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

or.

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

struct imaxdiv_t { std::intmax_t quot; std::intmax_t rem; };

or.

struct imaxdiv_t { std::intmax_t rem; std::intmax_t quot; };

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

Until C++11, 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 `std::div`

.

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.

#include <string> #include <cmath> #include <cstdlib> #include <iostream> std::string itoa(int n, int base) { std::string buf; std::div_t dv{}; dv.quot = n; do { dv = std::div(dv.quot, base); buf += "0123456789abcdef"[std::abs(dv.rem)]; // string literals are arrays } while(dv.quot); if(n<0) buf += '-'; return {buf.rbegin(), buf.rend()}; } int main() { std::cout << itoa(12345, 10) << '\n' << itoa(-12345, 10) << '\n' << itoa(65535, 16) << '\n'; }

Output:

12345 -12345 ffff

(C++11)(C++11) | remainder of the floating point division operation (function) |

(C++11)(C++11)(C++11) | signed remainder of the division operation (function) |

(C++11)(C++11)(C++11) | signed remainder as well as the three last bits of the division operation (function) |

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