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

From cppreference.com
< cpp‎ | container‎ | span

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 (C++20) | access the last element (public member function)

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