Thread: LZ77 Match Searching (HELP!)

I've learned LZ77 in theory, know I wanna practice, my first attempt was to code a C++ function that finds the best match when comparing the sliding window with the look ahead buffer, this is what i came up with: (btw it must return a array of int, 0->contains distance to run backwards from the lookahead buffer 1->contains how long the match is, it cant be less then 2)

Code:

#include <iostream>
#include <string>

using namespace std;

int * find_match(char * sliding_window, char * look_ahead)
{
    int distance = 0;
    int lenght = 0;

    // for loop runs every character pointed in var sliding_window
    // it searches for a character match longer than 2
    for(int x = 0; *(sliding_window+x) != '\0'; x++)
    {
        if(sliding_window[x] == look_ahead[0])
            if(sliding_window[x+1] == look_ahead[1])
                if(sliding_window[x+2] == look_ahead[2])
                {
                    //if reached here, then it means a match longer than 2 bytes has been found

                    // distance = ???? dont know how to calculate distance

                    lenght++; //previously 2, but 2 has already been checked if it matches, and it does
                    while(sliding_window[x+lenght] == look_ahead[lenght])
                        lenght++;

                }

        if(lenght > 0) // if it's bigger than 0, then it means it's already found a match
            break;
    }

    if(distance != 0 && lenght != 0)
    {
        int return_array[] = {distance,lenght};
        return return_array;
    }
    else
    {
        return 0;
    }
}

int main()
{
    char * str1 = "Just testing my function.";
    char * str2 = "I'm just testing.";
    int lenght_distance[] = find_match(str1, str2);
    cout << "distance: " << lenght_distance[0];
    return 0;
}

Somebody help me at making this function work, it's awful so far. And I can't call it on main without bumping into error report.