operator- (ranges::zip_view:: sentinel )

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operator- (zip_view:: iterator ,zip_view:: sentinel )
template < bool OtherConst >

requires ( std:: sized_sentinel_for <
ranges:: sentinel_t < /*maybe-const*/ < Const, Views >> ,
ranges:: iterator_t < /*maybe-const*/ < OtherConst, Views >>> && ... )
friend constexpr
std:: common_type_t < ranges:: range_difference_t < /*maybe-const*/ < OtherConst, Views >> ... >

operator - ( const iterator < OtherConst > & x, const sentinel & y ) ;
(1) (since C++23)
template < bool OtherConst >

requires ( std:: sized_sentinel_for <
ranges:: sentinel_t < /*maybe-const*/ < Const, Views >> ,
ranges:: iterator_t < /*maybe-const*/ < OtherConst, Views >>> && ... )
friend constexpr
std:: common_type_t < ranges:: range_difference_t < /*maybe-const*/ < OtherConst, Views >> ... >

operator - ( const sentinel & y, const iterator < OtherConst > & x ) ;
(2) (since C++23)

Computes the minimal distance between the underlying tuple of iterators of x and the underlying tuple of sentinels of y .

These functions are not visible to ordinary unqualified or qualified lookup , and can only be found by argument-dependent lookup when zip_view:: sentinel <Const> is an associated class of the arguments.

Parameters

x - an iterator
y - a sentinel

Return value

Let current_ denote the underlying tuple of iterators of x , and end_ denote the underlying tuple of sentinels of y .

Let DIST (x, y, i) be a distance calculated by expression equivalent to std :: get < i > ( x. current_ ) - std :: get < i > ( y. end_ ) for some integer i .

1) the value with the smallest absolute value among DIST (x, y, i) of all i in range 0 ≤ i < sizeof...(Views)
2) - ( x - y ) .

Example

Run this code 
#include <cassert>
#include <deque>
#include <list>
#include <ranges>
#include <vector>
 
int main()
{
    auto x = std::vector{1, 2, 3, 4};
    auto y = std::deque{'a', 'b', 'c'};
    auto z = {1.1, 2.2};
    auto w = std::list{1, 2, 3};
 
    auto p = std::views::zip(x, y, z);
    assert(p.begin() - p.end() == +2);
    assert(p.end() - p.begin() == -2);
 
    [[maybe_unused]]
    auto q = std::views::zip(x, y, w);
 
    // The following code fires a compile-time error because std::list::iterator
    // does not support operator- that is needed to calculate the distance:
    // auto e = q.begin() - q.end();
}
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