Memory & arrays - How to check if an index within a string array is empty?

#include <iostream>
#include <string>
#include <fstream>
#include <stdlib.h>
#include <stdio.h>

using namespace std;

class HashEntry
{
private:
    int keyInserted;
    int amount;

public:
    HashEntry(int keyInserted, int amount)
    {
        this->keyInserted = keyInserted;
        this->amount = amount;
    }

    int obtainKey()
    {
        return keyInserted;
    }

    int getValue()
    {
        return amount;
    }
};

const int TableSize = 100;

class HashMap
{
private:
    HashEntry **HashTable;

public:
    HashMap()
    {
        HashTable = new HashEntry*[TableSize];
        for (int i = 0; i < TableSize; i++)
            HashTable[i] = NULL;
    }

    int findPosition(int keyInserted)
    {
        int hash = (keyInserted % TableSize);
        int counter = 0;
        while (HashTable[hash] != NULL && HashTable[hash]->obtainKey() != keyInserted)
        {
            hash = (hash + 1) % TableSize;
            counter++;
        }
        if (HashTable[hash] == NULL) //if empty
            return -1;
        else
            return hash;
    }
    int Insert2(int keyInserted, int amount) //inserts a keyInserted and amount
    {
        int counter = 0;
        int quadratic = 1;
        int hash = (keyInserted % TableSize);
        int initial = hash;
        while (HashTable[hash] != NULL && HashTable[hash]->obtainKey() != keyInserted)
        {
            hash = (initial + ((quadratic * quadratic))) % TableSize;
            quadratic++;
            counter++;
        }
        if (HashTable[hash] != NULL)
            delete HashTable[hash];
        HashTable[hash] = new HashEntry(keyInserted, amount);
        return counter;
    }
    int searchState(int keyInserted)
    {
        int hash = (keyInserted % TableSize);
        int counter = 0;
        while (HashTable[hash] != NULL && HashTable[hash]->obtainKey() != keyInserted)
        {
            hash = (hash + 1) % TableSize;
            counter++;
        }
        if (HashTable[hash] == NULL) //if empty
            return -1;
        else
            return counter;
    }

    int Insert(int keyInserted, int amount)
    {
        int counter = 0;
        int hash = (keyInserted % TableSize);
        while (HashTable[hash] != NULL && HashTable[hash]->obtainKey() != keyInserted)
        {
            hash = (hash + 1) % TableSize;
            counter++;
        }
        if (HashTable[hash] != NULL)
            delete HashTable[hash];
        HashTable[hash] = new HashEntry(keyInserted, amount);
        return counter;
    }

    int searchState2(int keyInserted)
    {
        int hash = (keyInserted % TableSize);
        int counter = 0;
        int quadratic = 1;
        int initial = hash;
        while (HashTable[hash] != NULL && HashTable[hash]->obtainKey() != keyInserted)
        {
            hash = (initial + ((quadratic * quadratic))) % TableSize;
            quadratic++;
            counter++;
        }
        if (HashTable[hash] == NULL)
            return -1;
        else
            return counter;
    }

    int findPosition2(int keyInserted)
    {
        int hash = (keyInserted % TableSize);
        int counter = 0;
        int quadratic = 1;
        int initial = hash;

        while (HashTable[hash] != NULL && HashTable[hash]->obtainKey() != keyInserted)
        {
            hash = (initial + ((quadratic * quadratic))) % TableSize;
            quadratic++;
            counter++;
        }
        if (HashTable[hash] == NULL)
            return -1;
        else
            return hash;
    }

    ~HashMap()
    {
        for (int i = 0; i < TableSize; i++)
            if (HashTable[i] != NULL)
                delete HashTable[i];
        delete[] HashTable;
    }
};

int main()
{
    HashMap Hash;
    HashMap myHash2;
    string* temporary = new string[50] {};
    string* print = new string[100] {};
    string* print2 = new string[100] {};
    int clsn[100] = {0}, clsn2[100] = {0};
    int numCompare[100] = {0},numCompare2[100] = {0};
    int keyInserted[50] = {0}, i = 0, x = 0, y = 0;
    int ComparisonsAmount = 0, ComparisonsAmount2 = 0;
    int ComparisonsCount = 0, ComparisonsCount2 = 0;
    ifstream infile;
    infile.open ("a4.txt");
    if (infile.good())
    {
        while(infile.peek() != EOF)
        {
            infile >> temporary[i];
            for(y=0; y < temporary[i].length(); y++)
            {
                keyInserted[i] = keyInserted[i] + temporary[i][y];
            }
            Hash.Insert(keyInserted[i],i);
            myHash2.Insert2(keyInserted[i],i);
            Hash.findPosition(keyInserted[i]);
            myHash2.findPosition2(keyInserted[i]);
            print[Hash.findPosition(keyInserted[i])] = temporary[i];
            print2[myHash2.findPosition2(keyInserted[i])] = temporary[i];
            clsn[Hash.findPosition(keyInserted[i])] = Hash.Insert(keyInserted[i],i);
            clsn2[myHash2.findPosition2(keyInserted[i])] = myHash2.Insert2(keyInserted[i],i);
            numCompare[Hash.findPosition(keyInserted[i])] = Hash.searchState(keyInserted[i]);
            numCompare2[myHash2.findPosition2(keyInserted[i])] = myHash2.searchState2(keyInserted[i]);
            i++;
        }
    }
    else
    {
        cout << "a4.txt not found!";
        return -1;
    }
    infile.close();
    cout << "Linear Probing Hash Table: \n";
    for(x=0; x<100; x++)
    {
        if (x%4 == 0)
        {
            if(x < 10)
                cout << "\n" << "0" << x+1 << "|";
            else
                cout << "\n" << x+1 << "|";
        }
        print[x].resize(15,'_');
        cout << print[x] << clsn[x] << "|";
        if (clsn[x] > 0)
            ComparisonsCount++;
        ComparisonsAmount = numCompare[x] + ComparisonsAmount;
    }
    cout << endl;
    cout << "\nNumber of comparisons: " << ComparisonsAmount + ComparisonsCount << "\n";
    cout << endl;
    cout << "\nQuadratic Probing Hash Table: \n";
    for(x=0; x<100; x++)
    {
        if (x%4 == 0)
        {
            if(x < 10)
                cout << "\n" << "0" << x+1 << "|";
            else
                cout << "\n" << x+1 << "|";
        }
        print2[x].resize(15,'_');
        cout << print2[x] << clsn2[x] << "|";
        if (clsn2[x] > 0)
            ComparisonsCount2++;
        ComparisonsAmount2 = numCompare2[x] + ComparisonsAmount2;
    }
    cout << endl;
    cout << "\nNumber of comparisons: " << ComparisonsAmount2 + ComparisonsCount2;
    cout << endl;
    return 0;
}

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