std::vector<T,Allocator>::rend, std::vector<T,Allocator>::crend
来自 cppreference.cn
reverse_iterator rend(); |
(1) | (noexcept since C++11) (constexpr since C++20) |
const_reverse_iterator rend() const; |
(2) | (noexcept since C++11) (constexpr since C++20) |
const_reverse_iterator crend() const noexcept; |
(3) | (since C++11) (constexpr since C++20) |
返回指向逆序 vector
的最后一个元素之后元素的逆序迭代器。它对应于非逆序 vector
的首元素之前的元素。此元素充当占位符;尝试访问它会导致未定义行为。
内容 |
[编辑] 返回值
指向最后一个元素之后元素的逆序迭代器。
[编辑] 复杂度
常数。
注释
libc++ 向后移植 crend()
到 C++98 模式。
[编辑] 示例
运行此代码
#include <algorithm> #include <iostream> #include <numeric> #include <string> #include <vector> int main() { std::vector<int> nums{1, 2, 4, 8, 16}; std::vector<std::string> fruits{"orange", "apple", "raspberry"}; std::vector<char> empty; // Print vector. std::for_each(nums.rbegin(), nums.rend(), [](const int n) { std::cout << n << ' '; }); std::cout << '\n'; // Sums all integers in the vector nums (if any), printing only the result. std::cout << "Sum of nums: " << std::accumulate(nums.rbegin(), nums.rend(), 0) << '\n'; // Prints the first fruit in the vector fruits, checking if there is any. if (!fruits.empty()) std::cout << "First fruit: " << *fruits.rbegin() << '\n'; if (empty.rbegin() == empty.rend()) std::cout << "vector 'empty' is indeed empty.\n"; }
输出
16 8 4 2 1 Sum of nums: 31 First fruit: raspberry vector 'empty' is indeed empty.
[编辑] 参见
(C++11) |
返回指向起始的逆序迭代器 (公有成员函数) |
(C++14) |
返回容器或数组的逆序末尾迭代器 (函数模板) |