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HTTP/1.1 301 Moved Permanently
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Date: Sat, 19 Jul 2025 16:30:36 GMT
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Connection: keep-alive
Location: /reference/deque/deque/pop_front/
HTTP/1.1 200 OK
Server: nginx
Date: Sat, 19 Jul 2025 16:30:36 GMT
Content-Type: text/html; charset=utf-8
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Connection: keep-alive
ETag: W/"7a3d-fTvKNQRiWE4RYok1/v3LHKM8ZPo"
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Removes the first element in the deque container, effectively reducing its size by one.
This destroys the removed element.
Output:
Iterators, pointers and references referring to other elements that have not been removed are guaranteed to keep referring to the same elements they were referring to before the call.
The first element is modified. Concurrently accessing or modifying other elements is safe (although see iterator validity above).
Otherwise, the behavior is undefined.
Reference
C library:
- <cassert> (assert.h)
- <cctype> (ctype.h)
- <cerrno> (errno.h)
-
<cfenv> (fenv.h)C++11
- <cfloat> (float.h)
-
<cinttypes> (inttypes.h)C++11
- <ciso646> (iso646.h)
- <climits> (limits.h)
- <clocale> (locale.h)
- <cmath> (math.h)
- <csetjmp> (setjmp.h)
- <csignal> (signal.h)
- <cstdarg> (stdarg.h)
-
<cstdbool> (stdbool.h)C++11
- <cstddef> (stddef.h)
-
<cstdint> (stdint.h)C++11
- <cstdio> (stdio.h)
- <cstdlib> (stdlib.h)
- <cstring> (string.h)
-
<ctgmath> (tgmath.h)C++11
- <ctime> (time.h)
-
<cuchar> (uchar.h)C++11
- <cwchar> (wchar.h)
- <cwctype> (wctype.h)
Containers:
-
<array>C++11
- <deque>
-
<forward_list>C++11
- <list>
- <map>
- <queue>
- <set>
- <stack>
-
<unordered_map>C++11
-
<unordered_set>C++11
- <vector>
-
Input/Output:
Multi-threading:
-
<atomic>C++11
-
<condition_variable>C++11
-
<future>C++11
-
<mutex>C++11
-
<thread>C++11
-
Other:
- <algorithm>
- <bitset>
-
<chrono>C++11
-
<codecvt>C++11
- <complex>
- <exception>
- <functional>
-
<initializer_list>C++11
- <iterator>
- <limits>
- <locale>
- <memory>
- <new>
- <numeric>
-
<random>C++11
-
<ratio>C++11
-
<regex>C++11
- <stdexcept>
- <string>
-
<system_error>C++11
-
<tuple>C++11
-
<type_traits>C++11
-
<typeindex>C++11
- <typeinfo>
- <utility>
- <valarray>
deque
- deque::~deque
- deque::deque
member functions
- deque::assign
- deque::at
- deque::back
- deque::begin
-
deque::cbeginC++11
-
deque::cendC++11
- deque::clear
-
deque::crbeginC++11
-
deque::crendC++11
-
deque::emplaceC++11
-
deque::emplace_backC++11
-
deque::emplace_frontC++11
- deque::empty
- deque::end
- deque::erase
- deque::front
- deque::get_allocator
- deque::insert
- deque::max_size
- deque::operator[]
- deque::operator=
- deque::pop_back
- deque::pop_front
- deque::push_back
- deque::push_front
- deque::rbegin
- deque::rend
- deque::resize
-
deque::shrink_to_fitC++11
- deque::size
- deque::swap
non-member overloads
public member function
<deque>
std::deque::pop_front
void pop_front();
Delete first element
This destroys the removed element.
Parameters
noneReturn value
noneExample
|
|
Popping out the elements in mydeque: 100 200 300 The final size of mydeque is 0 |
Complexity
Constant.Iterator validity
The iterators, pointers and references referring to the removed element are invalidated.Iterators, pointers and references referring to other elements that have not been removed are guaranteed to keep referring to the same elements they were referring to before the call.
Data races
The container is modified.The first element is modified. Concurrently accessing or modifying other elements is safe (although see iterator validity above).
Exception safety
If the container is not empty, the function never throws exceptions (no-throw guarantee).Otherwise, the behavior is undefined.
See also
- deque::pop_back
- Delete last element (public member function)
- deque::push_front
- Insert element at beginning (public member function)
- deque::erase
- Erase elements (public member function)
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Spotted an error? contact us