Svenska ElektronikForumet

Kod: Markera allt

ptr = (start + end)/2; ger error: invalid operands to binary + (have ‘int *’ and ‘int *’) men,
ptr = start + (end - start)/2; fungerar

Kod: Markera allt

#define MY_ARCTAN_TABLE_SIZE ...
#define MY_ARCTAN_PI ...

/* Värden från 0 grader till 45 grader, index är (MY_ARCTAN_TABLE_SIZE * y)/x för y < x. */
int my_arctan_table[MY_ARCTAN_TABLE_SIZE] = {...};

int my_arctan2(int x, int y)
{
    if (x > 0) {
        if (y > 0) {
            return my_arctan2_bothpositive(x, y);
        } else if (y == 0) {
            return 0;
        } else {
            return 2 * MY_ARCTAN_PI - my_arctan2_bothpositive(x, -y);
        }
    } else if (x == 0) {
        if (y > 0) {
            return MY_ARCTAN_PI / 2;
        } else if (y == 0) {
            return 0;
        } else {
            return MY_ARCTAN_PI + MY_ARCTAN_PI / 2;
        }
    } else {
        if (y > 0) {
            return MY_ARCTAN_PI - my_arctan2_bothpositive(-x, y);
        } else if (y == 0) {
            return MY_ARCTAN_PI;
        } else {
            return MY_ARCTAN_PI + my_arctan2_bothpositive(-x, -y);
        }
    }
}

int my_arctan2_bothpositive(int x, int y)
{
    if (y < x) {
        return my_arctan_table[(MY_ARCTAN_TABLE_SIZE * y) / x];
    } else if (y == x) {
        return MY_ARCTAN_PI / 4;
    } else {
        return MY_ARCTAN_PI / 2 - my_arctan_table[(MY_ARCTAN_TABLE_SIZE * x) / y];
    }
}