Rbegin for C++

content/cpp/concepts/maps/terms/rbegin/rbegin.md

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+---
+Title: '.rbegin()'
+Description: 'Returns a reverse iterator pointing to the last element of the map.'
+Subjects:
+  - 'Code Foundations'
+  - 'Computer Science'
+Tags:
+  - 'Functions'
+  - 'Iterators'
+  - 'Maps'
+  - 'STL'
+CatalogContent:
+  - 'learn-c-plus-plus'
+  - 'paths/computer-science'
+---
+
+In C++, the **`.rbegin()`** function is used to obtain a reverse iterator pointing to the last element of a container, such as a vector, map, or other standard containers. This allows iteration from the end toward the beginning of the container. The `.rbegin()` function is typically used in conjunction with the `.rend()` function, which returns a reverse iterator pointing just before the first element of the container (i.e., the reverse end).
+
+## Syntax
+
+```pseudo
+container.rbegin();
+```
+
+**Parameters:**
+
+The `.rbegin()` function takes no parameters.
+
+**Return value:**
+
+The function returns a reverse iterator that points to the last element of the container. If the container contains no elements, the returned iterator will be equal to `.rend()`, indicating that there are no elements to iterate over in reverse.
+
+## Example
+
+The following exmaple demonstrates the usage of the `.rbegin()` function:
+
+```cpp
+#include <iostream>
+#include <map>
+
+int main() {
+  std::map<std::string, int> myMap = {{"one", 1}, {"two", 2}, {"three", 3}};
+  std::cout << "Elements in reverse order:\n";
+  for (auto it = myMap.rbegin(); it != myMap.rend(); ++it) {
+    std::cout << it->first << ": " << it->second << "\n";
+  }
+  return 0;
+}
+```
+
+The output of this code will be:
+
+```shell
+Elements in reverse order:
+three: 3
+two: 2
+one: 1
+```
+
+The `.rbegin()` function is used to obtain a reverse iterator that refers to the last element of the map. The loop iterates over the elements in reverse order, printing each key-value pair. The output shows the elements in reverse order compared to their original insertion order.
+
+## Codebyte Example
+
+Run the following code to understand how the `.rbegin()` function works:
+
+```codebyte/cpp
+#include <iostream>
+#include <map>
+
+int main() {
+  std::map<std::string, int> myMap = {{"one", 1}, {"two", 2}, {"three", 3}};
+  for (auto it = myMap.rbegin(); it != myMap.rend(); ++it) {
+    std::cout << it->first << ": " << it->second << "\n";
+  }
+  return 0;
+}
+```