Hashtable.cpp

#include <iostream>
using namespace std;
#include "Hashtable.h"
#include <vector>

Hashtable::Hashtable()
{
    start = nullptr;
}

void Hashtable::starthash()
{
    for (int i = 0; i < 12; i++)
    {
        Node * temp1 = new Node(i);
        if (start == nullptr)
        {
            start = temp1;
        }
        else
        {
            Node * current = start;
            while (current->next != nullptr)
            {
                current = current->next;
            }
            current->next = temp1;
        }
    }
    loadhashtable();
}

void Hashtable::add(int a, int p)
{
    static int i = 0;
    ofstream write;
    write.open("hashtable.txt", ios::app);
    if(i != 0)
    {
        write << endl;
        write << a << endl << p;
    }
    else
    {
        i++;
        write << a << endl << p;
    }
    write.close();
    starthash();
}

bool Hashtable::match(int a, int p)
{
    bool flag = false;
    int r = a % 10;
    Node * c = start;
    while (c->data != r)
    {
        c = c->next;
    }
    Node_1 *c1 = c->pres;
    while (c1 != nullptr)
    {
        if (c1->accountNumber == a && c1->password == p)
        {
            flag = true;
            break;
        }
        c1 = c1->next;
    }
    return flag;
}

void Hashtable::display()
{
    Node * current = start;
    while (current != nullptr)
    {
        cout << current->data << endl;
        current = current->next;
    }
}

void Hashtable::loadhashtable()
{
    int acc = 0, r, pass;
    read.open("hashtable.txt");
    while (!read.eof())
    {
        read >> acc;
        read >> pass;
        if (match(acc, pass))
        {
            continue;
        }
        if (acc!= -858993460 && pass!= -858993460)
		{
			r = acc % 10;

			Node * c = start;
			while (c->data != r)
			{
				c = c->next;
			}
			Node_1 *temp = new Node_1(acc, pass);
			if (c->pre == nullptr)
			{
				c->pre = temp;
			}
			else
			{
				Node_1 *root;
				root = c->pre;
				while (root->next != nullptr)
				{
					root = root->next;
				}
				root->next = temp;
			}
		}
        else
        {
            cout << "No Password Present" << endl;
        }
    }
    read.close();
}

void  Hashtable::displayPasswords()
{
	starthash();
	Node *c = start;
	while (c != nullptr)
	{
		Node_1 *c1 = c->pre;
		while (c1 != nullptr)
		{
			cout<< c1->accountNumber <<endl;
			cout<< c1->password <<endl;
			c1 = c1->next;
		}
		c = c->next;
	}
}
void  Hashtable:: delete_password(int accountno)
{
	ifstream read;
	read.open("hashtable.txt");
	vector <int> v;
	int acc=0, pass=0;
	int i = 0;
	while (!read.eof())
    {
        i++;
		read >> acc;
		read >> pass;
		if (acc == accountno)
		{// read both account number and password to skip them
			continue;
		}
		v.push_back(acc);
		v.push_back(pass);
	}
    read.close();
    ofstream write;
    write.open("temp.txt", ios::app);

    for (int i = 0; i < v.size(); i++)
    {
       if (v[i] != 0)
       {
            write << v[i] << endl;
       }
    }
    write.close();
    remove("hashtable.txt");
    rename("temp.txt", "hashtable.txt");
}