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

 

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Feature test macros (哋它亢++20)

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External libraries

 

Containers library

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array (哋它亢++11)

vector

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forward_list (哋它亢++11)

list

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unordered_set (哋它亢++11)

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Member function table

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std::forward_list

Member functions
forward_list::forward_list forward_list::~forward_list    forward_list::operator=	forward_list::assign forward_list::assign_range (哋它亢++23) 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::emplace_front forward_list::push_front forward_list::insert_after forward_list::emplace_after forward_list::erase_after	forward_list::insert_range_after (哋它亢++23) forward_list::prepend_range (哋它亢++23) 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
operator==operator!=operator<operator>operator<=operator>=operator<=> (哋它亢++11)(哋它亢++11)(until 哋它亢++20)(哋它亢++11)(until 哋它亢++20)(哋它亢++11)(until 哋它亢++20)(哋它亢++11)(until 哋它亢++20)(哋它亢++11)(until 哋它亢++20)(哋它亢++20)	swap(std::forward_list) (哋它亢++11) erase(std::forward_list)erase_if(std::forward_list) (哋它亢++20)(哋它亢++20)
Deduction guides(哋它亢++17)

 

reference front();	(1)	(since 哋它亢++11)
const_reference front() const;	(2)	(since 哋它亢++11)

Returns a reference to the first element in the container.

Calling front on an empty container causes undefined behavior.

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{'a', 'b', 'c', 'd', 'e', 'f'};
 
    if (!letters.empty())
        std::cout << "The first character is '" << letters.front() << "'.\n";
}

Output:

The first character is 'a'.

See also

push_front	inserts an element to the beginning (public member function)
pop_front	removes the first element (public member function)