NAME

std::vector::front - std::vector::front

Synopsis

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

Returns a reference to the first element in the container.

Calling front on an empty container is undefined.

Parameters

(none)

Return value

reference to the first element

Complexity

Constant

Notes

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

Example

The following code uses front to display the first element of a std::vector<char>:

// Run this code

#include <vector>
#include <iostream>

int main()
{
std::vector<char> letters {'o', 'm', 'g', 'w', 't', 'f'};

if (!letters.empty()) {
std::cout << "The first character is '" << letters.front() << "'.\n";
}
}

Output:

The first character is 'o'.