std::list<T,Allocator>:: begin, std::list<T,Allocator>:: cbegin
From cppreference.net
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iterator begin
(
)
;
|
(1) |
(noexcept since C++11)
(constexpr since C++26) |
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const_iterator begin
(
)
const
;
|
(2) |
(noexcept since C++11)
(constexpr since C++26) |
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const_iterator cbegin
(
)
const
noexcept
;
|
(3) |
(since C++11)
(constexpr since C++26) |
Returns an iterator to the first element of * this .
If * this is empty, the returned iterator will be equal to end() .
Contents |
Return value
Iterator to the first element.
Complexity
Constant.
Notes
libc++ backports
cbegin()
to C++98 mode.
Example
Run this code
#include <algorithm> #include <iostream> #include <numeric> #include <string> #include <list> int main() { std::list<int> nums{1, 2, 4, 8, 16}; std::list<std::string> fruits{"orange", "apple", "raspberry"}; std::list<char> empty; // Print list. std::for_each(nums.begin(), nums.end(), [](const int n) { std::cout << n << ' '; }); std::cout << '\n'; // Sums all integers in the list nums (if any), printing only the result. std::cout << "Sum of nums: " << std::accumulate(nums.begin(), nums.end(), 0) << '\n'; // Prints the first fruit in the list fruits, checking if there is any. if (!fruits.empty()) std::cout << "First fruit: " << *fruits.begin() << '\n'; if (empty.begin() == empty.end()) std::cout << "list 'empty' is indeed empty.\n"; }
Output:
1 2 4 8 16 Sum of nums: 31 First fruit: orange list 'empty' is indeed empty.
See also
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(C++11)
|
returns an iterator to the end
(public member function) |
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(C++11)
(C++14)
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returns an iterator to the beginning of a container or array
(function template) |