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

constexpr reference front() const;

Returns a reference to the first element in the span.

Calling front on an empty span results in undefined behavior.

Parameters

(none)

Return value

A reference to the first element.

Complexity

Constant

Notes

For a span c, the expression c.front() is equivalent to *c.begin().

Example

Run this code

#include <span>
#include <iostream>
 
void print(std::span<const int> const data)
{
    for (auto offset{0U}; offset != data.size(); ++offset) {
        std::cout << data.subspan(offset).front() << ' ';
    }
    std::cout << '\n';
}
 
int main()
{
    constexpr int data[] { 0, 1, 2, 3, 4, 5, 6 };
    print({data, 4});
}

Output:

0 1 2 3

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span (C++20)

Member functions
span::span
span::operator=
Element access
span::front
span::back
span::operator[]
span::data
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span::begin
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span::rbegin
span::rend
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span::empty
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span::size_bytes
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span::first
span::last
span::subspan
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as_bytesas_writable_bytes
Non-member constant
dynamic_extent
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