Div

Defined in headers <cstdlib>, <cinttypes>.

Description

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

Declarations

C++23

Defined in <cstdlib>

// 1)
constexpr std::div_t     div( int x, int y );
// 2)
constexpr std::ldiv_t    div( long x, long y );
// 3)
constexpr std::lldiv_t   div( long long x, long long y );
// 4)
constexpr std::ldiv_t   ldiv( long x, long y );
// 5)
constexpr std::lldiv_t lldiv( long long x, long long y );

Defined in <cinttypes>

// 6)
std::imaxdiv_t div( std::intmax_t x, std::intmax_t y );
// 7)
std::imaxdiv_t imaxdiv( std::intmax_t x, std::intmax_t y );

C++11

Defined in <cstdlib>

// 1)
std::div_t     div( int x, int y );
// 2)
std::ldiv_t    div( long x, long y );
// 3)
std::lldiv_t   div( long long x, long long y );
// 4)
std::ldiv_t   ldiv( long x, long y );
// 5)
std::lldiv_t lldiv( long long x, long long y );

Defined in <cinttypes>

// 6)
std::imaxdiv_t div( std::intmax_t x, std::intmax_t y );
// 7)
std::imaxdiv_t imaxdiv( std::intmax_t x, std::intmax_t y );

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, std::intmax_t, respectively), returns both as an object of type std::div_t, std::ldiv_t, std::lldiv_t, std::imaxdiv_t.

Examples

#include <cassert>
#include <cmath>
#include <cstdlib>
#include <iostream>
#include <sstream>
#include <string>
 
std::string euclidean_division_string(int dividend, int divisor)
{
    auto dv = std::div(dividend, divisor);
    assert(dividend == divisor * dv.quot + dv.rem);
    assert(dv.quot == dividend / divisor);
    assert(dv.rem == dividend % divisor);
 
    auto sign = [](int n){ return n > 0 ? 1 : n < 0 ? -1 : 0; };
    assert((dv.rem == 0) or (sign(dv.rem) == sign(dividend)));
 
    return (std::ostringstream() 
        << std::showpos << dividend << " = "
        << divisor << " * (" << dv.quot << ") "
        << std::showpos << dv.rem).str();
}
 
std::string itoa(int n, int radix /*[2..16]*/)
{
    std::string buf;
    std::div_t dv{}; dv.quot = n;
 
    do
    {
        dv = std::div(dv.quot, radix);
        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 
        << euclidean_division_string(369, 10) << '\n'
        << euclidean_division_string(369, -10) << '\n'
        << euclidean_division_string(-369, 10) << '\n'
        << euclidean_division_string(-369, -10) << "\n\n";
 
    std::cout 
        << itoa(12345, 10) << '\n'
        << itoa(-12345, 10) << '\n'
        << itoa(42, 2) << '\n'
        << itoa(65535, 16) << '\n';
}

Result

+369 = +10 * (+36) +9
+369 = -10 * (-36) +9
-369 = +10 * (-36) -9
-369 = -10 * (+36) -9
 
12345
-12345
101010
ffff