Hash Table

//linklist_impl.hpp
#include<string>
using namespace std;
class linklist
{
    int c;
    struct node
    {
    public:
        string data;
        node *link;
    } *p;
public:
    linklist();
    void append(string &str);
    void del(string &str);
    void display();
    string getData();
    int searchlist(string);
    bool isListEmpty();
    ~linklist();
};

//linklist_impl.cpp
#include <iostream>
#include <string>
#include <cstring>
#include "linklist_impl.hpp"
using namespace std;


linklist::linklist()
{
    p = NULL;
    c = 0;
}

void linklist::append(string &str)
{
    node *q, *t;
    if(p==NULL)
    {
        p = new node;
        p->data = str;
        p->link = NULL;
        c += 1;
    }
    else
    {
        q = p;
        while(q->link != NULL)
        {
            q = q->link;
        }
        t = new node;
        t->data = str;
        t->link = NULL;
        q->link = t;
        c += 1;
    }
}

void linklist::del(string &str)
{
    node *q, *r;
    q = p;
    if(q->data == str)
    {
        p = q->link;
        delete q;
        c -= 1;
        return;
    }
    r = q;
    while(q != NULL)
    {
        if(q->data == str)
        {
            r->link = q->link;
            delete q;
            c -= 1;
            return;
        }
        r = q;
        q = q->link;
    }
    cout<<"Element "<<str<<" not found"<<endl;
}

void linklist::display()
{
    node *q;
    int i;
    for(q = p, i = 0; q != NULL, i < c; q = q->link, i++)
    {
        cout<<"\t"<<i<<": "<<q->data<<endl;
    }
}

string linklist::getData()
{
  return p->data;
}

bool linklist::isListEmpty()
{
    node *q;
    int i,flag = 0;
    for(q = p, i = 0; q != NULL, i < c; q = q->link, i++)
    {
      if(q->data != "")
        flag = 1;
    }
    if(flag == 1)
      return false;
    else
      return true;
}

int linklist::searchlist(string searchItem)
{
    node *q;
    int i;
    for(q = p, i = 0; q != NULL, i < c; q = q->link, i++)
    {
      if(q -> data == searchItem)
        return i;
    }
    return -1;
}

linklist::~linklist()
{
    node *q;
    if(p == NULL)
    {
        return;
    }
    while(p != NULL)
    {
        q = p->link;
        delete p;
        p = q;
    }
}


</cstring></string></iostream>

//schashtable.cpp
#include<iostream>
#include<sys/time.h>
#include<stdlib.h>
#include<stdio.h>
#include<limits>
#include<cstring>
#include "linklist_impl.hpp"

using namespace std;
struct timeval starttime,endtime,timediff;
enum {FILLED = 0 , ALL};
const int sizeHTable = 5;


class table
{

private:
    linklist *items;
    int nel;
    int strhash(const char *str);
public:
    table(int size);
    ~table();
    void addItem();
    int searchTable(string);
    void delItem();
    void display( int mode);
    int getCount();
    bool isEmpty();
};

#define BAD_INPUT_CUTOFF 3
unsigned int getIntInRange(unsigned int min, unsigned int max,
                           const char *prompt)
{
    int input, //used to get input
    bad_count=0; //used to keep track of how many bad attempts.
    do
    {
        std::cout << prompt;
        std::cin >> input;
        if (!std::cin.good() || input < min || input > max)
        {
            std::cout << "\nInvalid Input!" << std::endl;
            std::cin.clear(); //resets the state flag
            
//clears out the buffer
std::cin.ignore(std::numeric_limits<std::streamsize>::max(),'\n');
                   
            bad_count++; //User made a bad input, count it
            input = 0;   // user did not enter a valid number
        }
        //See if this is a valid number (users are mean/stupid sometimes)
    }
    while (input == 0 && bad_count < BAD_INPUT_CUTOFF);
    return input;
}


table::table(int size)
{
    items = new linklist[size];
    for(int i = 0; i<sizeHTable ;i++)
    nel = 0;
}

table::~table()
{  
    if(items)
    delete[] items;
}

int table::strhash(const char *str) {
    unsigned long hash = 0;
      int i=0;
        while(i <= strlen(str)) {
              hash = hash + (hash<<5) + (unsigned long)(str[i]);
                  i++;
                    }
          return (hash%sizeHTable); //return the hashed number which must be 
                                    //between 0 an size-1, this is why I used
                                    //hash%size
}

void table::addItem()
{
        string str;
        
        cout<<"\nEnter Data : ";
        cin>>str;

        
        int i = strhash(str.c_str());
        if( i >= 0 && i < sizeHTable )
        {
            items[i].append(str);
            cout<<"\nInserted";
            nel++;
            return;
        }

}

int table::searchTable(string searchItem)
{
    int pos;
    
    int i = strhash(searchItem.c_str());

    if((pos = items[i].searchlist(searchItem)) != -1 )
    {
        cout<<"Bucket["<<i<<"] -> pos : "<<pos<<"\t" <<"\t"<< endl;
        return i;
    }
    else
    {
            cout<<"Data "<<searchItem<<" not present in the table" << endl;
            return -1;
    }
}

void table::delItem()
{
    string item;
    cout<<"\nEnter an item to delete : ";
    cin>>item;
    
    int index;
    index = strhash(item.c_str());
        items[index].del(item);
        nel--;
}

bool table::isEmpty()
{
    if( nel > 0)
    {
        return false;
    }
    else
    {
        cout<<"\nTable is Empty"<<endl;
        return true;
    }
}

void table::display(int mode = FILLED)
{
    if(isEmpty())
        return;

   if(mode == FILLED)
   {
     int i;
     for(i=0; i<sizeHTable; i++)
     { 
        if(items[i].isListEmpty() == false)
        {
          cout<<"Bucket["<<i<<"] :"<<endl;
          items[i].display(); //call the function of our linked list,
                              //which outputs it's records with their indexes
        }
     }
   } 
   else if(mode == ALL)
   {
     int i;
     for(i=0; i<sizeHTable; i++)
     {
        cout<<"Bucket["<<i<<"] :"<<endl;
        items[i].display(); //call the function of our linked list,
                            //which outputs it's records with their indexes
     }
   } 
}

int table::getCount()
{
    return nel;
}

int main()
{
    int choice;
    
    string item;
    table T1(sizeHTable);
    int mode;

    while(1)
    {
        choice = getIntInRange(1,6,"\n1.Add New Item\n2.Delete Item
                 \n3.Search Item \n4.Display Hash Table \n5.Get the
                  number of elements \n6.Exit\nEnter your choice : ");
        
            switch(choice)
            {
            case 1 :
                T1.addItem();
                break;
            case 2 :
                T1.delItem();
                break;
            case 3 :
                if(T1.isEmpty() != true)
                {
                    cout<<"\nEnter an item to search : ";
                    cin>>item;
                    T1.searchTable(item);
                }
                break;
            case 4 :
                cout<<"\nEnter display mode (0 - FILLED / 1- ALL) : ";
                cin>>mode;
                T1.display(mode);
                break;
             case 5 :
                cout<<"Total no. of elements : "<<T1.getCount()<<endl;
                break;
             case 6 :
                exit(0);
            }
        
    }
    
    
}