NAME¶

std::span::front - std::span::front

Synopsis¶

constexpr reference front() const; (since C++20)

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 <iostream>
#include <span>

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

See also¶

back access the last element
(public member function)