void getHistory (GameView gv, PlayerID player, LocationID trail[TRAIL_SIZE])
{
    //Check if its the beginning of the game
    if (gv->roundNumber == 0) {
        int trailC = 0;
        while(trailC < TRAIL_SIZE){//add UNKNOWN_LOCATION to entire trail
            trail[trailC] = UNKNOWN_LOCATION;
            trailC++;
        }
    } else {
        //find latest play index in pastP
        int lastPlay = latestPlay(gv);
        while(pastP[lastPlay] != player){
            lastPlay = lastPlay - PLAY_LEN;
        }//latest play by player

        //now we fill in the trail, finally.
        int countr = 0;
        while(countr < TRAIL_SIZE){
            char currLoc[2];
            //extract location abbreviation
            currLoc[0] = pastP[lastPlay+1];
            currLoc[1] = pastP[lastplay+2];
            currLoc[2] = '\0';

            //turn location abbreviation to locationID
            LocationID currLocation = abbrevToID(currLoc);

            //finally, add locationID to trail
            pushToTrail(trail, currLocation);

            lastPlay = lastPlay - LINE_LEN;//go back to the previous round
            countr++;//will only go to 6 to ensure trail is at most last 6 plays.
        }
        //after all of this the trail array should be updated for
        //whichever player was parsed into the function.
    }
}

//local function to push location onto trail. oldest location falls off trail.
static void pushToTrail(LocationID trail[TRAIL_SIZE], LocationID location){
    assert(trail != NULL);
    int i = 0;
    LocationID temp = trail[i];
    while(trail[i] != '\0'){
        //tests to see if were adding to end of array
        if(i+1 == TRAIL_SIZE){
            trail[i] = location;
            i++;//increments and then loop ends.

        } else {//operation to shift numbers along array.
            trail[i] = location;
            location = temp;
            temp = trail[i+1];
            i++;
        }
    }
}