From 0431f5b485b8542015912b87b439b807db9cefa2 Mon Sep 17 00:00:00 2001
From: Durgesh kumar prajapati <98798977+Durgesh4993@users.noreply.github.com>
Date: Tue, 11 Oct 2022 13:00:16 +0530
Subject: [PATCH] Create Hash map in cpp

---
 Hash map in cpp | 92 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 92 insertions(+)
 create mode 100644 Hash map in cpp

diff --git a/Hash map in cpp b/Hash map in cpp
new file mode 100644
index 0000000..7ed2c5e
--- /dev/null
+++ b/Hash map in cpp	
@@ -0,0 +1,92 @@
+// Hash map class template
+template <typename K, typename V, typename F = KeyHash<K>>
+class HashMap {
+public:
+    HashMap() {
+        // construct zero initialized hash table of size
+        table = new HashNode<K, V> *[TABLE_SIZE]();
+    }
+
+    ~HashMap() {
+        // destroy all buckets one by one
+        for (int i = 0; i < TABLE_SIZE; ++i) {
+            HashNode<K, V> *entry = table[i];
+            while (entry != NULL) {
+                HashNode<K, V> *prev = entry;
+                entry = entry->getNext();
+                delete prev;
+            }
+            table[i] = NULL;
+        }
+        // destroy the hash table
+        delete [] table;
+    }
+
+    bool get(const K &key, V &value) {
+        unsigned long hashValue = hashFunc(key);
+        HashNode<K, V> *entry = table[hashValue];
+
+        while (entry != NULL) {
+            if (entry->getKey() == key) {
+                value = entry->getValue();
+                return true;
+            }
+            entry = entry->getNext();
+        }
+        return false;
+    }
+
+    void put(const K &key, const V &value) {
+        unsigned long hashValue = hashFunc(key);
+        HashNode<K, V> *prev = NULL;
+        HashNode<K, V> *entry = table[hashValue];
+
+        while (entry != NULL && entry->getKey() != key) {
+            prev = entry;
+            entry = entry->getNext();
+        }
+
+        if (entry == NULL) {
+            entry = new HashNode<K, V>(key, value);
+            if (prev == NULL) {
+                // insert as first bucket
+                table[hashValue] = entry;
+            } else {
+                prev->setNext(entry);
+            }
+        } else {
+            // just update the value
+            entry->setValue(value);
+        }
+    }
+
+    void remove(const K &key) {
+        unsigned long hashValue = hashFunc(key);
+        HashNode<K, V> *prev = NULL;
+        HashNode<K, V> *entry = table[hashValue];
+
+        while (entry != NULL && entry->getKey() != key) {
+            prev = entry;
+            entry = entry->getNext();
+        }
+
+        if (entry == NULL) {
+            // key not found
+            return;
+        }
+        else {
+            if (prev == NULL) {
+                // remove first bucket of the list
+                table[hashValue] = entry->getNext();
+            } else {
+                prev->setNext(entry->getNext());
+            }
+            delete entry;
+        }
+    }
+
+private:
+    // hash table
+    HashNode<K, V> **table;
+    F hashFunc;
+};