array::rbegin() and array::rend() in C++ STL
- array::rbegin() is a built-in function in C++ STL which returns a reverse iterator pointing to the last element in the container. Syntax:
array_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 array::rbegin() method: Program 1:
CPP
// CPP program to illustrate // the array::rbegin() function #include <bits/stdc++.h> using namespace std; int main() { // array initialisation array< int , 5> arr = { 1, 5, 2, 4, 7 }; // prints the last element cout << "The last element is " << *(arr.rbegin()) << endl; // prints all the elements cout << "The array elements in reverse order are:\n" ; for ( auto it = arr.rbegin(); it != arr.rend(); it++) cout << *it << " " ; return 0; } |
Output:
The last element is 7 The array elements in reverse order are: 7 4 2 5 1
Time Complexity: O(N) where N is the size of the array.
Auxiliary Space: O(1)
- array::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 array container. Syntax:
array_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 array container. Program to demonstrate the array::rend() method: Program 1:
CPP
// CPP program to illustrate // the array::rend() function #include <bits/stdc++.h> using namespace std; int main() { array< int , 5> arr = { 1, 5, 2, 4, 7 }; // prints all the elements cout << "The array elements in reverse order are:\n" ; for ( auto it = arr.rbegin(); it != arr.rend(); it++) cout << *it << " " ; return 0; } |
Output:
The array elements in reverse order are: 7 4 2 5 1
Time Complexity: O(N) where N is the size of the array.
Auxiliary Space: O(1)
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