C++ vector::rbegin() Function

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The C++ vector::rbegin() function is used to return the reverse iterator pointing to the vector's final element. A reverse iterator iterates backward, and increase in its result, advances the vector container to the beginning. Similar reducing a reverse iterator causes the vector container to move to the end. The time complexity of the rbegin() function is constant.

In contrast to the back() function, which returns a direct reference to the last element, this function returns the reverse iterator pointing to the same element of the vector.

Syntax

Following is the syntax for C++ vector::rbegin() Function −

reverse_iterator rbegin() noexcept;const_reverse_iterator rbegin() const noexcept;

Parameters

It doesn't contains any kind of parameters.

Example 1

Let's consider the following example, where we are going to use the rbegin() function.

#include <iostream>
#include <vector>
using namespace std;

int main(void){
   vector<int> v = {1, 2, 3, 4, 5};
   for (auto it =  v.rbegin(); it != v.rend(); ++it)
      cout << *it << endl;
   return 0;
}

Output

When we compile and run the above program, this will produce the following result −

5
4
3
2
1

Example 2

Considering the another scenario, where we are going to take the char type.

#include <iostream>
#include<vector>
using namespace std;

int main(){
   vector<char> myvector{'T','L','E','Z','U','R','C'};
   vector<char>::reverse_iterator x;
   for(x=myvector.rbegin(); x!=myvector.rend(); x++)
      std::cout<< *x;
   return 0;
}

Output

On running the above program, it will produce the following result −

CRUZELT

Example 3

In the following example, we are going to use the push_back() function to insert the elements and getting the last element of the vector.

#include <iostream>
#include <vector>
using namespace std;

int main(){
   vector<int> myvector;
   myvector.push_back(22);
   myvector.push_back(44);
   myvector.push_back(6);
   myvector.push_back(8);
   vector<int>::reverse_iterator x;
   x = myvector.rbegin();
   cout << "Last Element Is : " << *x << endl;
   return 0;
}

Output

When we execute the above program, it will produce the following result −

Last Element Is : 8

Example 4

Following is the example, where we are going to take the string typr and applying the rbegin() function.

#include <iostream>
#include <vector>
using namespace std;

int main (){
   vector<string> foodchain{"Tiger","Cow ->","Tree ->"};
   vector<string>::reverse_iterator x;
   x = foodchain.rbegin();
   cout<<*x<<" ";
   x++;
   cout<<*x<<" ";
   x++;
   cout<<*x<<" ";
   return 0;
}

Output

On running the above program, it will produce the following result −

Tree -> Cow ->  Tiger