fcfs992.cpp

#include<iostream>
#include <list>
using namespace std;
 
class Hash
{
    int BUCKET;    // No. of buckets
 
    // Pointer to an array containing buckets
    list<int> *table;
public:
    Hash(int V);  // Constructor
 
    // inserts a key into hash table
    void insertItem(int x);
 
    // deletes a key from hash table
    void deleteItem(int key);
 
    // hash function to map values to key
    int hashFunction(int x) {
        return (x % BUCKET);
    }
 
    void displayHash();
};
 
Hash::Hash(int b)
{
    this->BUCKET = b;
    table = new list<int>[BUCKET];
}
 
void Hash::insertItem(int key)
{
    int index = hashFunction(key);
    table[index].push_back(key); 
}
 
void Hash::deleteItem(int key)
{
  // get the hash index of key
  int index = hashFunction(key);
 
  // find the key in (inex)th list
  list <int> :: iterator i;
  for (i = table[index].begin();
           i != table[index].end(); i++) {
    if (*i == key)
      break;
  }
 
  // if key is found in hash table, remove it
  if (i != table[index].end())
    table[index].erase(i);
}
 
// function to display hash table
void Hash::displayHash() {
  for (int i = 0; i < BUCKET; i++) {
    cout << i;
    for (auto x : table[i])
      cout << " --> " << x;
    cout << endl;
  }
}
 
// Driver program 
int main()
{
  // array that contains keys to be mapped
  int a[] = {15, 11, 27, 8, 12};
  int n = sizeof(a)/sizeof(a[0]);
 
  // insert the keys into the hash table
  Hash h(7);   // 7 is count of buckets in
               // hash table
  for (int i = 0; i < n; i++) 
    h.insertItem(a[i]);  
 
  // delete 12 from hash table
  h.deleteItem(12);
 
  // display the Hash table
  h.displayHash();
 
  return 0;
}