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

reference front();	(1)
const_reference front() const;	(2)

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::deque<char>:

Run this code

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

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deque::deque
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deque::get_allocator
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deque::at
deque::operator[]
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deque::begindeque::cbegin (C++11)
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deque::clear
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deque::emplace_front (C++11)
deque::prepend_range (C++23)
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