fix chaining

hashing/chaining.cpp

@@ -1,20 +1,54 @@
-#include <math.h>
+/**
+ * @file chaining.cpp
+ * @author [vasutomar](https://github.com/vasutomar)
+ * @author [Krishna Vedala](https://github.com/kvedala)
+ * @brief
+ */
+#include <cmath>
 #include <iostream>
-using namespace std;
+#include <memory>
+#include <vector>
 
+namespace {  // keep the code local to this file by assigning them to an unnamed
+             // namespace
+/**
+ * @{
+ * @brief Define a linked node
+ */
 struct Node {
-    int data;
+    int data{};                         ///< data stored in the node
-    struct Node *next;
+    std::shared_ptr<struct Node> next;  ///< pointer to the next node
-} * head[100], *curr;
+};
 
-void init() {
+/**
-    for (int i = 0; i < 100; i++) head[i] = NULL;
+ * @brief Chain class with a given modulus
+ */
+class chain {
+ private:
+    std::vector<std::shared_ptr<struct Node>> head;  ///< array of nodes
+    int _mod;                                        ///< modulus of the class
+
+ public:
+    /**
+     * @brief Construct a new chain object
+     *
+     * @param mod modulus of the chain
+     */
+    chain(int mod) : _mod(mod) {
+        while (mod--) head.push_back(nullptr);
     }
 
+    /**
+     * @brief create and add a new node with a give value and at a given height
+     *
+     * @param x value at the new node
+     * @param h height of the node
+     */
     void add(int x, int h) {
-    struct Node *temp = new Node;
+        std::shared_ptr<struct Node> curr;
+        std::shared_ptr<struct Node> temp(new struct Node);
         temp->data = x;
-    temp->next = NULL;
+        temp->next = nullptr;
         if (!head[h]) {
             head[h] = temp;
             curr = head[h];
@@ -25,86 +59,104 @@ void add(int x, int h) {
         }
     }
 
-void display(int mod) {
+    /**
-    struct Node *temp;
+     * @brief Display the chain
-    int i;
+     */
-    for (i = 0; i < mod; i++) {
+    void display() {
+        std::shared_ptr<struct Node> temp = nullptr;
+        int i = 0;
+        for (i = 0; i < _mod; i++) {
             if (!head[i]) {
-            cout << "Key " << i << " is empty" << endl;
+                std::cout << "Key " << i << " is empty" << std::endl;
             } else {
-            cout << "Key " << i << " has values = ";
+                std::cout << "Key " << i << " has values = ";
                 temp = head[i];
                 while (temp->next) {
-                cout << temp->data << " ";
+                    std::cout << temp->data << " ";
                     temp = temp->next;
                 }
-            cout << temp->data;
+                std::cout << temp->data;
-            cout << endl;
+                std::cout << std::endl;
             }
         }
     }
 
-int hash(int x, int mod) { return x % mod; }
+    /**
+     * @brief Compute the hash of a value for current chain
+     *
+     * @param x value to compute modulus of
+     * @return modulus of `x`
+     */
+    int hash(int x) const { return x % _mod; }
 
     void find(int x, int h) {
-    struct Node *temp = head[h];
+        auto temp = head[h];
         if (!head[h]) {
-        cout << "Element not found";
+            std::cout << "Element not found";
             return;
         }
         while (temp->data != x && temp->next) temp = temp->next;
-    if (temp->next)
+        if (temp->next) {
-        cout << "Element found";
+            std::cout << "Element found";
-    else {
+        } else {
-        if (temp->data == x)
+            if (temp->data == x) {
-            cout << "Element found";
+                std::cout << "Element found";
-        else
+            } else {
-            cout << "Element not found";
+                std::cout << "Element not found";
             }
         }
+    }
+};
+
+}  // namespace
+
+/** Main function
+ * @returns `0` always
+ */
+int main() {
+    int c = 0, x = 0, mod = 0, h = 0;
+    std::cout << "Enter the size of Hash Table. = ";
+    std::cin >> mod;
+
+    chain mychain(mod);
 
-int main(void) {
-    init();
-    int c, x, mod, h;
-    cout << "Enter the size of Hash Table. = ";
-    cin >> mod;
     bool loop = true;
     while (loop) {
-        cout << endl;
+        std::cout << std::endl;
-        cout << "PLEASE CHOOSE -" << endl;
+        std::cout << "PLEASE CHOOSE -" << std::endl;
-        cout << "1. Add element." << endl;
+        std::cout << "1. Add element." << std::endl;
-        cout << "2. Find element." << endl;
+        std::cout << "2. Find element." << std::endl;
-        cout << "3. Generate Hash." << endl;
+        std::cout << "3. Generate Hash." << std::endl;
-        cout << "4. Display Hash table." << endl;
+        std::cout << "4. Display Hash table." << std::endl;
-        cout << "5. Exit." << endl;
+        std::cout << "5. Exit." << std::endl;
-        cin >> c;
+        std::cin >> c;
         switch (c) {
             case 1:
-            cout << "Enter element to add = ";
+                std::cout << "Enter element to add = ";
-            cin >> x;
+                std::cin >> x;
-            h = hash(x, mod);
+                h = mychain.hash(x);
-            h = fabs(h);
+                h = std::fabs(h);
-            add(x, h);
+                mychain.add(x, h);
                 break;
             case 2:
-            cout << "Enter element to search = ";
+                std::cout << "Enter element to search = ";
-            cin >> x;
+                std::cin >> x;
-            h = hash(x, mod);
+                h = mychain.hash(x);
-            find(x, h);
+                mychain.find(x, h);
                 break;
             case 3:
-            cout << "Enter element to generate hash = ";
+                std::cout << "Enter element to generate hash = ";
-            cin >> x;
+                std::cin >> x;
-            cout << "Hash of " << x << " is = " << hash(x, mod);
+                std::cout << "Hash of " << x << " is = " << mychain.hash(x);
                 break;
             case 4:
-            display(mod);
+                mychain.display();
                 break;
             default:
                 loop = false;
                 break;
         }
-        cout << endl;
+        std::cout << std::endl;
     }
     /*add(1,&head1);
     add(2,&head1);