Called function clears changes of previous one

Question

I'm working on a cellular automaton where changes happen in every rounds. Obviously, I made a loop for it - basically it works, fortunately, but if I want to add another type of cells to the map, one type of cells works, but the other doesn't do anything: the game begins and e.g. in this example, the Conway-automaton starts growing, but the red test-cells are just staying without any changes.

#define fldwidth 110 
#define fldheight 140

typedef struct tiles
{
    unsigned char red, green, blue;
}tiles;

const tiles TEST_ALIVE = {255,0,0};
const tiles TEST_DEAD = {50,0,0};
const tiles CONWAY_ALIVE = {0,255,0};
const tiles CONWAY_DEAD = {0,50,0};

//Maes módszere a struktúrák egyenlőségének vizsgálatára
bool equality(tiles* a, const tiles* b) 
{
    if (a->red == b->red && a->green == b->green && a->blue == b->blue)
    {
        return true;
    } else {
        return false;
    }
}



//sejttípus 1.: tesztsejt: minden magányos vagy túlbuzgó sejt meghal
void Test(tiles arra[fldwidth][fldheight], tiles arrb[fldwidth][fldheight])
{
    int a,b,i,j,counter;

    for (j=1;j<fldheight-1;j++)
    {
        for (i=1;i<fldwidth-1;i++)
        {
            if (equality(&arra[i][j], &TEST_ALIVE) == true)
            {
            counter = -1;
            } else {
                counter = 0;
            }
            for (b=j-1;b<=j+1;b++)
            {
                for (a=i-1;a<=i+1;a++)
                {
                    if (equality(&arra[a][b], &TEST_ALIVE) == true)
                    {
                        counter+=1;
                    }
                }
            }
            arrb[i][j] = arra[i][j];
            //itt a sejtek szabályai jönnek; mindig a születést tesszük előre, utána a halált!
            if (equality(&arra[i][j], &TEST_ALIVE) == false && counter >= 2)
            {
                arrb[i][j] = TEST_ALIVE;
            }

            if (equality(&arra[i][j], &TEST_ALIVE) == true && (counter == 0 || counter > 6))
            {
                arrb[i][j] = TEST_DEAD;
            }
        }
    }

}

//sejttípus 2.: Conway életjátéka
void Conway(tiles arra[fldwidth][fldheight], tiles arrb[fldwidth][fldheight])
{
    int a,b,i,j,counter;

    for (j=1;j<fldheight-1;j++)
    {
        for (i=1;i<fldwidth-1;i++)
        {
            if (equality(&arra[i][j], &CONWAY_ALIVE) == true)
            {
            counter = -1;
            } else {
                counter = 0;
            }
            for (b=j-1;b<=j+1;b++)
            {
                for (a=i-1;a<=i+1;a++)
                {
                    if (equality(&arra[a][b], &CONWAY_ALIVE) == true)
                    {
                        counter+=1;
                    }
                }
            }
            arrb[i][j] = arra[i][j];
            //itt a sejtek szabályai jönnek; mindig a születést tesszük előre, utána a halált!
            if (equality(&arra[i][j], &CONWAY_ALIVE) == false && counter == 3)
            {
                arrb[i][j] = CONWAY_ALIVE;
            }

            if (equality(&arra[i][j], &CONWAY_ALIVE) == true && (counter != 2 && counter != 3))
            {
                arrb[i][j] = CONWAY_DEAD;
            }
        }
    }
}

This is content of the loop:

Test(fielda,fieldb);
Conway(fielda,fieldb);
end = false;
round++;
for (j = 0; j < fldheight; j++)
    {
        for (i = 0; i < fldwidth; i++)
        {
            fielda[i][j] = fieldb[i][j];
        }
    }

As I mentioned, in this example, Conway cells grow, but Test cells just stay. How to make them work simultaneously?

(I use Allegro libraries so if that has something for this problem, feel free to share with me!)

Answer 1

Test(fielda,fieldb); sets every cell of fieldb based on the current value of fielda. And then Conway(fielda,fieldb); sets every cell of fieldb based on the current value of fielda, overwriting fieldb so that everything Test did is gone. One way to fix this is to change your loop to:

Test(fielda,fieldb);
Conway(fieldb,fielda);  //switched the parameters
end = false;
round++;
//there is no need to copy fieldb to fielda here because Conway already did

But this might not be the right fix depending on exactly how you want test and conway to interact with each other.