Optimize string search in .txt file

This might be a really stupid question, but how do I optimize this code in making it more effiecient (faster,less memory consuming)? I made this code to help me sort some text files. It reads each string from the first file, then it searches through the second file until it finds all related strings, and in a third file it writes some matched strings. Here is the code:

ifstream h("SecondFile.txt");
ifstream h2("FirstFile.txt");
ifstream uh("MatchedStrings.txt");
ofstream g("sorted.txt");    
int main()
    {
        string x, y, z;
        cout << "Sorting..." << endl;;
        while (!h.eof()){
            h >> x;
            while (!h2.eof() || (y == x)){
                h2 >> y;
                uh >> z;
                if (y == x){
                    g << z << endl;
                    break;
                    h2.clear();
                    h2.seekg(0);
                    uh.clear();
                    uh.seekg(0);
                }
            }
            if (h2.eof() && (y != x)){
                g << "none" << endl;
                h2.clear();
                h2.seekg(0);
                uh.clear();
                uh.seekg(0);
            }
        }
        cout << "Finished!";
    }

I have changed my code to this:

#include <iostream>
#include <fstream>
#include <string>

using namespace std;
ifstream h("SecondFile.txt");
ifstream h2("FirstFile.txt");
ifstream uh("MatchedStrings.txt");
ofstream g("sorted.txt");

int main()
{
    string x;
    bool write_none = true;
    int i = 0,l=0;
    string check[] = {""};
    string unhashed_checked[] = { "" };
    string sorted_array[] = { "" };
    cout << "Sorting..." << endl;
    //Get to memory
    while (!h2.eof())
    {
        h2 >> check[i];
        uh >> unhashed_checked[i];
        i++;
    }

    while (!h.eof()){
        h >> x;
        write_none = true;
        for (int t = 0; t <= i;t++)
        {
            if (x == check[t])
            {
                break;
                write_none = false;
                sorted_array[l] = unhashed_checked[i];
                l++;
            }
        }
        if (write_none)
        {
            sorted_array[l] = "none";
            l++;
        }
    }
    for (int k = 0; k <= l; k++)
    {
        g << sorted_array[k]<<endl;
    }
    cout << "Finished!";
}

But I am getting this exception when running the program:

Unhandled exception at 0x01068FF6 in ConsoleApplication1.exe: 0xC0000005: Access violation writing location 0xCCCCCCCC