operator+,-(ranges::enumerate_view::iterator)

From cppreference.com
 
 
Ranges library
Range adaptors
 
 
friend constexpr /* iterator */

    operator+( const /* iterator */& i, difference_type n )

    requires ranges::random_access_range</* Base */>;
(1) (since C++23)
friend constexpr /* iterator */

    operator+( difference_type n, const /* iterator */& i )

    requires ranges::random_access_range</* Base */>;
(2) (since C++23)
friend constexpr /* iterator */

    operator-( const /* iterator */& i, difference_type n )

    requires ranges::random_access_range</* Base */>;
(3) (since C++23)
friend constexpr difference_type
    operator-( const /* iterator */& i, const /* iterator */& j ) noexcept;
(4) (since C++23)

Performs iterator arithmetic or calculates the distance.

pos_ is the underlying index, and Base is the (possibly const-qualified) type of underlying view.

Equivalent to:

1) auto temp = i; temp += n; return temp;
2) return i + n;
3) auto temp = i; temp -= n; return temp;
4) return i.pos_ - j.pos_;

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

Parameters

i, j - the iterators
n - position relative to current location

Return value

1,2) An incremented iterator.
3) A decremented iterator.
4) A distance between given iterators.

Example

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR Applied to Behavior as published Correct behavior
LWG 3912 C++23 overload (4) was not noexcept it is noexcept

See also

advances or decrements the underlying iterator
(public member function)