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      std::vector<T,Allocator>::rbegin,std::vector<T,Allocator>::crbegin

      From cppreference.com
      <cpp‎ |container‎ |vector

      [edit template]
       
       
       
      std::vector
      Member types
      Member functions
      Non-member functions
      (until C++20)(until C++20)(until C++20)(until C++20)(until C++20)
      Deduction guides(C++17)
       
      reverse_iterator rbegin();
      (1)(noexcept since C++11)
      (constexpr since C++20)
      const_reverse_iterator rbegin()const;
      (2)(noexcept since C++11)
      (constexpr since C++20)
      const_reverse_iterator crbegin()constnoexcept;
      (3)(since C++11)
      (constexpr since C++20)

      Returns a reverse iterator to the first element of the reversed*this. It corresponds to the last element of the non-reversed*this.

      If*this is empty, the returned iterator is equal torend().

      range-rbegin-rend.svg

      Contents

      [edit]Return value

      Reverse iterator to the first element.

      [edit]Complexity

      Constant.

      [edit]Notes

      Theunderlying iterator of the returned reverse iterator is theend iterator. Hence the returned iterator is invalidated if and when the end iterator is invalidated.

      libc++ backportscrbegin() to C++98 mode.

      [edit]Example

      Run this code
      #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(),[](constint 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";}

      Output:

      16 8 4 2 1Sum of nums: 31First fruit: raspberryvector 'empty' is indeed empty.

      [edit]See also

      (C++11)
      returns a reverse iterator to the end
      (public member function)[edit]
      returns a reverse iterator to the beginning of a container or array
      (function template)[edit]
      Retrieved from "https://en.cppreference.com/mwiki/index.php?title=cpp/container/vector/rbegin&oldid=162066"

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