Merge pull request #191 from MohamedKamal98/master

Create a Hash Map DS example

data_structures/Hash Map/HashMap.cpp

@@ -0,0 +1,72 @@
+#include "HashMap.h"
+
+
+
+HashMap::HashMap()
+{
+	table = new HashEntry *[TABLE_SIZE];
+	for (int i = 0; i < TABLE_SIZE; i++)
+	{
+		table[i] = NULL;
+	}
+}
+
+int HashMap::HashFunc(int key)
+{
+	return key % TABLE_SIZE;
+}
+void HashMap::Insert(int key, int value)
+{
+	int hash = HashFunc(key);
+	while (table[hash] != NULL && table[hash]->key != key)
+	{
+		hash = HashFunc(hash + 1);
+	}
+	if (table[hash] != NULL)
+		delete table[hash];
+	table[hash] = new HashEntry(key, value);
+}
+
+int HashMap::Search(int key)
+{
+	int  hash = HashFunc(key);
+	while (table[hash] != NULL && table[hash]->key != key)
+	{
+		hash = HashFunc(hash + 1);
+	}
+	if (table[hash] == NULL)
+		return -1;
+	else
+		return table[hash]->value;
+}
+
+void HashMap::Remove(int key)
+{
+	int hash = HashFunc(key);
+	while (table[hash] != NULL)
+	{
+		if (table[hash]->key == key)
+			break;
+		hash = HashFunc(hash + 1);
+	}
+	if (table[hash] == NULL)
+	{
+		cout << "No Element found at key " << key << endl;
+		return;
+	}
+	else
+	{
+		delete table[hash];
+	}
+	cout << "Element Deleted" << endl;
+}
+
+HashMap::~HashMap()
+{
+	for (int i = 0; i < TABLE_SIZE; i++)
+	{
+		if (table[i] != NULL)
+			delete table[i];
+		delete[] table;
+	}
+}

data_structures/Hash Map/HashMap.h

@@ -0,0 +1,31 @@
+#pragma once
+#include<iostream>
+#include<cstdlib>
+#include<string>
+#include<cstdio>
+using namespace std;
+const int TABLE_SIZE = 128;
+
+class HashEntry
+{
+public:
+	int key;
+	int value;
+	HashEntry(int key, int value)
+	{
+		this->key = key;
+		this->value = value;
+	}
+};
+
+class HashMap
+{
+	HashEntry **table;
+public:
+	HashMap();
+	int HashFunc(int key);
+	void Insert(int key, int value);
+	int Search(int key);
+	void Remove(int key);
+	~HashMap();
+};

data_structures/Hash Map/Source.cpp

@@ -0,0 +1,54 @@
+#include "HashMap.h"
+
+int main()
+{
+	HashMap hash;
+	int key, value;
+	int choice;
+	while (1)
+	{
+		cout << "\n----------------------" << endl;
+		cout << "Operations on Hash Table" << endl;
+		cout << "\n----------------------" << endl;
+		cout << "1.Insert element into the table" << endl;
+		cout << "2.Search element from the key" << endl;
+		cout << "3.Delete element at a key" << endl;
+		cout << "4.Exit" << endl;
+		cout << "Enter your choice: ";
+		cin >> choice;
+		switch (choice)
+		{
+		case 1:
+			cout << "Enter element to be inserted: ";
+			cin >> value;
+			cout << "Enter key at which element to be inserted: ";
+			cin >> key;
+			hash.Insert(key, value);
+			break;
+		case 2:
+			cout << "Enter key of the element to be searched: ";
+			cin >> key;
+			if (hash.Search(key) == -1)
+			{
+				cout << "No element found at key " << key << endl;
+				continue;
+			}
+			else
+			{
+				cout << "Element at key " << key << " : ";
+				cout << hash.Search(key) << endl;
+			}
+			break;
+		case 3:
+			cout << "Enter key of the element to be deleted: ";
+			cin >> key;
+			hash.Remove(key);
+			break;
+		case 4:
+			exit(1);
+		default:
+			cout << "\nEnter correct option\n";
+		}
+	}
+	return 0;
+}