std::forward_list<T,Allocator>::front

 

C++

Compiler support

Freestanding and hosted

Language

Standard library headers

Named requirements

Feature test macros (C++20)

Language support library

Concepts library (C++20)

Metaprogramming library (C++11)

Diagnostics library

General utilities library

Strings library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Numerics library

Localizations library

Input/output library

Filesystem library (C++17)

Regular expressions library (C++11)

Concurrency support library (C++11)

Technical specifications

Symbols index

External libraries

 

Containers library

Sequence

array (C++11)

vector

deque

forward_list (C++11)

list

Associative

set

multiset

map

multimap

Unordered associative

unordered_set (C++11)

unordered_multiset (C++11)

unordered_map (C++11)

unordered_multimap (C++11)

Adaptors

stack

queue

priority_queue

Views

span (C++20)

 

std::forward_list

Member functions

forward_list::forward_list

forward_list::~forward_list

forward_list::operator=

forward_list::assign

forward_list::get_allocator

Element access

forward_list::front

Iterators

forward_list::before_beginforward_list::cbefore_begin

forward_list::beginforward_list::cbegin

forward_list::endforward_list::cend

Capacity

forward_list::empty

forward_list::max_size

Modifiers

forward_list::clear

forward_list::insert_after

forward_list::emplace_after

forward_list::erase_after

forward_list::push_front

forward_list::emplace_front

forward_list::pop_front

forward_list::resize

forward_list::swap

Operations

forward_list::merge

forward_list::splice_after

forward_list::removeforward_list::remove_if

forward_list::reverse

forward_list::unique

forward_list::sort

Non-member functions

std::swap

eraseerase_if (C++20)(C++20)

operator==operator!=operator<operator>operator<=operator>=operator<=> (until C++20)(until C++20)(until C++20)(until C++20)(until C++20)(C++20)

Deduction guides(C++17)

 

reference front();		(since C++11)
const_reference front() const;		(since C++11)

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::forward_list<char>:

Run this code

#include <forward_list>
#include <iostream>
 
int main()
{
    std::forward_list<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'.