Add the initial EN translation for C++ code (#1346)

en/codes/cpp/chapter_hashing/array_hash_map.cpp

@@ -0,0 +1,110 @@
+/**
+ * File: array_hash_map.cpp
+ * Created Time: 2022-12-14
+ * Author: msk397 (machangxinq@gmail.com)
+ */
+
+#include "../utils/common.hpp"
+
+/* Key-value pair */
+struct Pair {
+  public:
+    int key;
+    string val;
+    Pair(int key, string val) {
+        this->key = key;
+        this->val = val;
+    }
+};
+
+/* Hash table based on array implementation */
+class ArrayHashMap {
+  private:
+    vector<Pair *> buckets;
+
+  public:
+    ArrayHashMap() {
+        // Initialize an array, containing 100 buckets
+        buckets = vector<Pair *>(100);
+    }
+
+    ~ArrayHashMap() {
+        // Free memory
+        for (const auto &bucket : buckets) {
+            delete bucket;
+        }
+        buckets.clear();
+    }
+
+    /* Hash function */
+    int hashFunc(int key) {
+        int index = key % 100;
+        return index;
+    }
+
+    /* Query operation */
+    string get(int key) {
+        int index = hashFunc(key);
+        Pair *pair = buckets[index];
+        if (pair == nullptr)
+            return "";
+        return pair->val;
+    }
+
+    /* Add operation */
+    void put(int key, string val) {
+        Pair *pair = new Pair(key, val);
+        int index = hashFunc(key);
+        buckets[index] = pair;
+    }
+
+    /* Remove operation */
+    void remove(int key) {
+        int index = hashFunc(key);
+        // Free memory and set to nullptr
+        delete buckets[index];
+        buckets[index] = nullptr;
+    }
+
+    /* Get all key-value pairs */
+    vector<Pair *> pairSet() {
+        vector<Pair *> pairSet;
+        for (Pair *pair : buckets) {
+            if (pair != nullptr) {
+                pairSet.push_back(pair);
+            }
+        }
+        return pairSet;
+    }
+
+    /* Get all keys */
+    vector<int> keySet() {
+        vector<int> keySet;
+        for (Pair *pair : buckets) {
+            if (pair != nullptr) {
+                keySet.push_back(pair->key);
+            }
+        }
+        return keySet;
+    }
+
+    /* Get all values */
+    vector<string> valueSet() {
+        vector<string> valueSet;
+        for (Pair *pair : buckets) {
+            if (pair != nullptr) {
+                valueSet.push_back(pair->val);
+            }
+        }
+        return valueSet;
+    }
+
+    /* Print hash table */
+    void print() {
+        for (Pair *kv : pairSet()) {
+            cout << kv->key << " -> " << kv->val << endl;
+        }
+    }
+};
+
+// See test case in array_hash_map_test.cpp