implementation of unordered map

unordered_map.cpp

@@ -0,0 +1,135 @@
+#include<iostream>
+#include<vector>
+#include<list>
+
+using namespace std;
+
+
+#define SIZE 100
+
+template <class A,class B>
+class unordered_map{
+
+private:
+
+	vector< list <pair <A, B> > > map;
+
+public:
+
+	unordered_map() {
+		map.resize(SIZE);
+	}
+
+	int calculate_hash(int key) {
+
+	    key = ((key >> 16) ^ key) * 0x45d9f3b;
+	    key = ((key >> 16) ^ key) * 0x45d9f3b;
+	    key = (key >> 16) ^ key;
+	    return key;
+
+	}
+
+
+
+	int calculate_hash(string key)
+	{
+
+       int seed = 131; 
+       unsigned long hash = 0;
+       for(int i = 0; i < key.length(); i++)
+       {
+          hash = (hash * seed) + key[i];
+       }
+
+       return hash;
+
+   } 
+
+
+
+
+	void insert(A key,B value)
+	{
+		int flag=0;
+		int index = calculate_hash(key)%SIZE;
+		for(auto it=map[index].begin();it!=map[index].end();it++)
+		{
+			if(it->first==key)
+			 {
+			 	it->second=value;
+			 	flag=1;
+			 	break;
+			 }
+
+		}
+
+
+			 if(!flag)
+			  map[index].push_back(make_pair(key,value));	
+
+	}
+
+
+
+	void deleteEle(A key, B value)
+	{
+		int flag=0;
+		int index = calculate_hash(key)%SIZE;
+
+		for(auto it=map[index].begin();it!=map[index].end();it++)
+		{
+			if(it->first==key)
+			 {
+			 	flag=1;
+			 	map[index].remove(make_pair(key,value));
+			 	break;
+			 }
+		}
+
+		if(!flag)
+		 cout<<"element doesnot exist";
+
+	}
+
+
+	void search(A key)
+	{
+		int flag=0;
+		int index = calculate_hash(key)%SIZE;
+
+		for(auto it=map[index].begin();it!=map[index].end();it++)
+		{
+			if(it->first==key)
+			 {
+			 	cout<<"value is"<<it->second;
+			 	return ;
+			 }
+		}
+
+
+		 cout<<"element doesnot exist";
+
+
+	}
+
+
+	void display()
+	{
+		for(int i = 0; i < map.size(); i++) {
+			for(auto it=map[i].begin();it!=map[i].end();it++) {
+				cout<< it->first << " " << it->second;
+			}
+		}
+	}
+};
+
+int main()
+{
+	unordered_map<string,int> mp;
+	mp.insert("hey",12);
+	mp.display();
+	mp.search("hey");
+	mp.deleteEle("bi",9);
+
+	return 0;
+}