Cpp hash function

content/cpp/concepts/unordered-set/terms/hash-function/hash-function.md

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+---
+Title: hash_function()'
+Description: 'Returns the hash function object used by the unordered set.'
+Subjects:
+  - 'Code Foundations'
+  - 'Computer Science'
+Tags:
+  - 'Data Structures'
+  - 'Elements'
+  - 'Hash Maps'
+  - 'Sets'
+CatalogContent:
+  - 'learn-c-plus-plus'
+  - 'paths/computer-science'
+---
+
+The **`hash_function()`** returns the hash function object used by the [`unordered_set`](https://www.codecademy.com/resources/docs/cpp/unordered-set) container.
+
+
+## Syntax
+
+```pseudo
+unordered_set.hash_function();
+```
+
+**Parameters:**
+
+This method takes no parameters.
+
+**Return value:**
+
+The `hash_function()` returns the hash function.
+
+## Example: Using `hash_function()` to return the hash function
+
+In this example, `hash_function()` is used to return the hash function of an element in an `unordered_set`:
+
+```cpp
+#include <iostream>
+#include <unordered_set>
+
+int main() {
+    std::unordered_set<int> s = {10, 20, 30};
+
+    // get the hash function
+    auto hf = s.hash_function();
+
+    std::cout << "Hash of 10: " << hf(10) << std::endl;
+    std::cout << "Hash of 20: " << hf(20) << std::endl;
+}
+```
+
+The output for this code is:
+
+```shell
+Hash of 10: 10
+Hash of 20: 20
+```
+
+> **Note:** The output may vary depending on the specific C++ implementation and hash function.
+
+## Codebyte Example: Inserting a new element into an unordered set
+
+In this example, the code demonstrates how to retrieve and use the hash function from an unordered_set to compute hash values for its elements.
+
+```codebyte/cpp
+#include <iostream>
+#include <unordered_set>
+
+int main() {
+    std::unordered_set<int> values = {10, 20, 30};
+
+    // Retrieve the hash function used by the unordered_set
+    auto hashFunc = values.hash_function();
+
+    // Display hash values of elements
+    for (int v : values) {
+        std::cout << "Value: " << v
+                  << ", Hash: " << hashFunc(v) << std::endl;
+    }
+
+    return 0;
+}
+```
+