std::counted_iterator<I>:: count

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C++
Iterator library
Iterator concepts
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(C++20)
(C++20)
(C++20)
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(C++20)
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(C++11) (C++14)
(C++14) (C++14)
(C++11) (C++14)
(C++14) (C++14)
(C++17) (C++20)
(C++17)
(C++17)
std::counted_iterator
constexpr std:: iter_difference_t < I > count ( ) const noexcept ;
(since C++20)

Returns the underlying length that is the distance to the end.

Parameters

(none)

Return value

The underlying length .

Example

Run this code 
#include <cassert>
#include <iostream>
#include <iterator>
 
int main()
{
    constexpr static auto il = {1, 2, 3, 4, 5};
    constexpr std::counted_iterator i1{il.begin() + 1, 3};
    static_assert(i1.count() == 3);
    auto i2{i1};
    for (; std::default_sentinel != i2; ++i2)
        std::cout << "*i2: " << *i2 << ", count(): " << i2.count() << '\n';
    assert(i2.count() == 0);
}

Output: 

*i2: 2, count(): 3
*i2: 3, count(): 2
*i2: 4, count(): 1

See also

(C++20)
accesses the underlying iterator
(public member function)
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