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# vector rbegin() and rend() function in C++ STL

vector::rbegin() is a built-in function in C++ STL which returns a reverse iterator pointing to the last element in the container.
Syntax:

`vector_name.rbegin()`

Parameters: The function does not accept any parameter.
Return value: The function returns a reverse iterator pointing to the last element in the container.
Program to demonstrate the vector::rbegin() method:
Program 1:

## CPP

 `// CPP program to illustrate``// the vector::rbegin() function``#include ``using` `namespace` `std;` `int` `main()``{``    ``vector<``int``> v;``    ``v.push_back(11);``    ``v.push_back(12);``    ``v.push_back(13);``    ``v.push_back(14);``    ``v.push_back(15);` `    ``// prints all the elements``    ``cout << "The vector elements in reverse order are:\n";``    ``for` `(``auto` `it = v.rbegin(); it != v.rend(); it++)``        ``cout << *it << " ";``    ``return` `0;``}`

Output:

```The vector elements in reverse order are:
15 14 13 12 11```

Time Complexity – constant O(1)

vector::rend() is a built-in function in C++ STL which returns a reverse iterator pointing to the theoretical element right before the first element in the vector container.
Syntax:

`vector_name.rend()`

Parameters: The function does not take any parameter.
Return value: The function returns a reverse iterator pointing to the theoretical element right before the first element in the vector container.
Program to demonstrate the vector::rend() method:
Program 1:

## CPP

 `// CPP program to illustrate``// the vector::rend() function``#include ``using` `namespace` `std;` `int` `main()``{``    ``vector<``int``> v;``    ``v.push_back(11);``    ``v.push_back(12);``    ``v.push_back(13);``    ``v.push_back(14);``    ``v.push_back(15);` `    ``cout << "The last element is: " << *v.rbegin();` `    ``// prints all the elements``    ``cout << "\nThe vector elements in reverse order are:\n";``    ``for` `(``auto` `it = v.rbegin(); it != v.rend(); it++)``        ``cout << *it << " ";``    ``return` `0;``}`

Output:

```The last element is: 15
The vector elements in reverse order are:
15 14 13 12 11```

Time Complexity – constant O(1)

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