GeeksforGeeks App
Open App
Browser
Continue

# map rbegin() function in C++ STL

The std::map::rbegin() is a function in C++ STL. It returns a reverse iterator which points to the last element of the map. The reverse iterator iterates in reverse order and incrementing it means moving towards beginning of map.

Syntax:

```r_i rbegin();
const_r_i rbegin() const;```

Parameters: It does not except any parameters.

Returns: It returns a reverse iterator which points to the last element of the map.

Time Complexity: O(1)

Below examples illustrate the map::rbegin() method:

Example 1:

 `// C++ Program to illustrate``// map::rbegin() method`` ` `#include ``#include ``using` `namespace` `std;`` ` `int` `main()``{`` ` `    ``map<``char``, ``int``> mp = {``        ``{ ``'a'``, 1 },``        ``{ ``'b'``, 2 },``        ``{ ``'c'``, 3 },``        ``{ ``'d'``, 4 },``        ``{ ``'e'``, 5 },``    ``};`` ` `    ``cout << ``"Map contains following "``         ``<< ``"elements in reverse order"``         ``<< endl;`` ` `    ``for` `(``auto` `i = mp.rbegin(); i != mp.rend(); ++i)``        ``cout << i->first``             ``<< ``" = "` `<< i->second``             ``<< endl;`` ` `    ``return` `0;``}`

Output:

```Map contains following elements in reverse order
e = 5
d = 4
c = 3
b = 2
a = 1
```

Example 2:

 `// C++ Program to illustrate``// map::rbegin() method`` ` `#include ``#include ``using` `namespace` `std;`` ` `int` `main()``{`` ` `    ``map<``char``, ``char``> mp = {``        ``{ ``'a'``, ``'A'` `},``        ``{ ``'b'``, ``'B'` `},``        ``{ ``'c'``, ``'C'` `},``        ``{ ``'d'``, ``'D'` `},``        ``{ ``'e'``, ``'E'` `},``    ``};`` ` `    ``cout << ``"Map contains following "``         ``<< ``"elements in reverse order"``         ``<< endl;`` ` `    ``for` `(``auto` `i = mp.rbegin(); i != mp.rend(); ++i)``        ``cout << i->first``             ``<< ``" = "` `<< i->second``             ``<< endl;`` ` `    ``return` `0;``}`

Output:

```Map contains following elements in reverse order
e = E
d = D
c = C
b = B
a = A
```

My Personal Notes arrow_drop_up