added sample LRU

LRU.cpp

+#include <iostream>
+#include <string>
+#include <vector>
+#include <pthread.h>
+#include <map>
+#include <bits/stdc++.h> 
+
+struct KV{
+    char *key;
+    char *value;
+    bool valid;
+    bool modified;
+
+};
+typedef struct KV KV;
+
+using namespace std;
+
+int MAX_SIZE=10;
+map<char *,int> mp;
+vector<KV *> stor;
+deque<char *> dq;
+
+
+void remove_element_from_deque(char *key)
+{
+    for (auto it = dq.begin(); it != dq.end(); it++) 
+    {
+        if(*it == key)
+        {
+            dq.erase(it);
+            break;
+        }
+    }
+}
+
+int find_empty_location()
+{
+    for(int i=0;i<MAX_SIZE;i++)
+    {
+        if(stor[i]->valid == 0)
+            return i;
+    }
+}
+
+void delet(char *key)
+{
+    remove_element_from_deque(key);
+    int indx = mp[key];
+    mp.erase(key);
+    stor[indx]->valid = 0;
+    //TODO remove key from file also
+}
+
+void put(char *key, char *value)
+{
+    int indx=-1;
+    if(mp.find(key) != mp.end())
+    {
+        indx = mp[key];
+        remove_element_from_deque(key);
+    }
+    else
+    {
+        indx = find_empty_location();
+        mp[key] = indx;
+        // TODO should write to file if modified is true
+        // replacment from cache
+    }
+
+    stor[indx]->key = key;
+    stor[indx]->value = value;
+    stor[indx]->valid = 1;
+    stor[indx]->modified = 1;
+    dq.push_front(key);
+}
+
+char* get(char *key)
+{
+    if(mp.find(key) != mp.end())
+    {
+        int indx = mp[key];
+        remove_element_from_deque(key);
+        dq.push_front(key);
+        return stor[indx]->value;
+    }
+    return (char *)"NOT FOUND";
+}
+
+int main()
+{
+    // stor.resize(10);
+    stor.resize(10);
+
+    int i=0;
+    for(int j=0;j<MAX_SIZE;j++)
+    {
+        stor[j] = (KV *)malloc(sizeof(KV));
+        stor[j]->valid = false;
+    }
+    char key1[250]="Hello world1";
+    char value1[256] = "THIS IS  Vlaue1";
+
+    char key2[250]="Hello world2";
+    char value2[256] = "THIS IS  Vlaue2";
+
+    char key3[250]="Hello world3";
+    char value3[256] = "THIS IS  Vlaue3";
+
+    char key4[250]="Hello world4";
+    char value4[256] = "THIS IS  Vlaue4";
+
+    char key5[250]="Hello world5";
+    char value5[256] = "THIS IS  Vlaue5";
+
+    char key6[250]="Hello world6";
+    char value6[256] = "THIS IS  Vlaue6";
+
+
+    KV  *temp1 = (KV *)malloc(sizeof(KV));
+    KV  *temp2 = (KV *)malloc(sizeof(KV));
+    KV  *temp3 = (KV *)malloc(sizeof(KV));
+    KV  *temp4 = (KV *)malloc(sizeof(KV));
+    KV  *temp5 = (KV *)malloc(sizeof(KV));
+    KV  *temp6 = (KV *)malloc(sizeof(KV));
+
+    temp1->key = key1;
+    temp1->value = value1;
+    temp1->valid = 1;
+
+    temp2->key = key2;
+    temp2->value = value2;
+    temp2->valid = 1;
+
+    temp3->key = key3;
+    temp3->value = value3;
+    temp3->valid = 1;
+
+    temp4->key = key4;
+    temp4->value = value4;
+    temp4->valid = 1;
+
+    temp5->key = key5;
+    temp5->value = value5;
+    temp5->valid = 1;
+
+    temp6->key = key6;
+    temp6->value = value6;
+    temp6->valid = 1;
+
+
+    stor[i++]=(temp1);
+    stor[i++] = (temp2);
+    stor[i++] = (temp3);
+    stor[i++] = (temp4);
+    stor[i++] = (temp5);
+    stor[i++] = (temp6);
+
+    mp.insert({key6,5});
+    mp.insert({key1,0});
+    mp.insert({key2,1});
+    mp.insert({key3,2});
+    mp.insert({key4,3});
+    mp.insert({key5,4});
+    
+    cout << mp.size() << endl;
+    cout << stor[0]->key << " " << stor[0]->value << endl;
+    cout << stor[1]->key << " " << stor[1]->value << endl;
+    cout << stor[2]->key << " " << stor[2]->value << endl;
+    cout << stor[3]->key << " " << stor[3]->value << endl;
+    cout << stor[4]->key << " " << stor[4]->value << endl;
+    cout << stor[5]->key << " " << stor[5]->value << endl;
+
+    cout << get(stor[5]->key) << endl;
+    put(stor[5]->key, (char *)"This is a good");
+    cout << get(stor[5]->key) << endl;
+    delet(stor[5]->key);
+        
+    delet(stor[0]->key);
+
+    put((char *)"Hello World7", (char *)"THis is vaue7");
+
+    cout << stor[0]->key << " " << stor[0]->value << "\n";
+
+    return 0;
+}