[Term Entry] C++ Unordered-sets: empty()

* Add C++ unordered-set empty() term entry

* minor content fixes

* Update empty.md

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Author: ylevental

content/cpp/concepts/unordered-set/terms/empty/empty.md

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+---
+Title: '.empty()'
+Description: 'Checks whether the unordered set is empty.'
+Subjects:
+  - 'Computer Science'
+  - 'Game Development'
+Tags:
+  - 'Containers'
+  - 'Functions'
+  - 'Sets'
+  - 'STL'
+CatalogContent:
+  - 'learn-c-plus-plus'
+  - 'paths/computer-science'
+---
+
+The **`.empty()`** method checks whether an `unordered_set` has no elements. It returns `true` if the container is empty (i.e., its size is 0) and `false` otherwise.
+
+## Syntax
+
+```pseudo
+unordered_set_name.empty()
+```
+
+**Parameters:**
+
+This method does not take any parameters.
+
+**Return value:**
+
+Returns `true` if the `unordered_set` is empty and `false` otherwise.
+
+## Example
+
+The following example demonstrates how to use the `.empty()` method with `std::unordered_set` in C++:
+
+```cpp
+#include <iostream>
+#include <unordered_set>
+
+int main() {
+  std::unordered_set<int> numbers;
+
+  if (numbers.empty()) {
+    std::cout << "Unordered set is empty\n";
+  } else {
+    std::cout << "Unordered set has elements\n";
+  }
+
+  numbers.insert(10);
+  numbers.insert(20);
+  numbers.insert(30);
+
+  if (numbers.empty()) {
+    std::cout << "Unordered set is empty\n";
+  } else {
+    std::cout << "Unordered set has elements\n";
+  }
+
+  return 0;
+}
+```
+
+The output of the above code is:
+
+```shell
+Unordered set is empty
+Unordered set has elements
+```
+
+## Codebyte Example
+
+In this example, the `.empty()` method is used to control a loop that processes and removes elements from an `unordered_set` until it becomes empty:
+
+```codebyte/cpp
+#include <iostream>
+#include <unordered_set>
+
+int main() {
+  std::unordered_set<int> numbers = {5, 10, 15, 20, 25};
+
+  std::cout << "Processing elements: ";
+
+  while (!numbers.empty()) {
+    auto it = numbers.begin();
+    std::cout << *it << " ";
+    numbers.erase(it);
+  }
+
+  std::cout << "\n";
+  std::cout << "Unordered set is now empty? - " << std::boolalpha << numbers.empty() << "\n";
+
+  return 0;
+}
+```