std::span<T,Extent>::begin

 

C++

Language

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Named requirements

Language support library

Concepts library (C++20)

Diagnostics library

Utilities library

Strings library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Numerics library

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Filesystem library (C++17)

Regular expressions library (C++11)

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Technical Specifications

 

Containers library

array (C++11)

vector

deque

forward_list (C++11)

list

set

multiset

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multimap

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unordered_multiset (C++11)

unordered_map (C++11)

unordered_multimap (C++11)

stack

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span (C++20)

 

std::span

Member functions

span::span

span::operator=

Element access

span::front

span::back

span::operator[]

span::data

Iterators

span::begin

span::end

span::rbegin

span::rend

Observers

span::empty

span::size

span::size_bytes

Subviews

span::first

span::last

span::subspan

Non-member functions

as_bytesas_writable_bytes

Non-member constant

dynamic_extent

Deduction guides

 

constexpr iterator begin() const noexcept;

Returns an iterator to the first element of the span.

If the span is empty, the returned iterator will be equal to end().

Parameters

(none)

Return value

Iterator to the first element.

Complexity

Constant.

Example

Run this code

#include <span>
#include <iostream>
 
void print(std::span<const int> sp)
{
    for(auto it = sp.begin(); it != sp.end(); ++it) {
        std::cout << *it << ' ';
    }
    std::cout << '\n';
}
 
void transmogrify(std::span<int> sp)
{
    if (!sp.empty()) {
        std::cout << *sp.begin() << '\n';
        *sp.begin() = 2;
    }
}
 
int main()
{
    int array[] { 1, 3, 4, 5 };
    print(array);
    transmogrify(array);
    print(array);
}

Output:

1 3 4 5 
1
2 3 4 5

See also

end	returns an iterator to the end (public member function)