void swap(triangle *trA, triangle *trB) {
    triangle temp = *trA;
    *trA = *trB;
    *trB = temp;
}

float getArea(triangle tr) {
    float p = ((float)tr.a + (float)tr.b + (float)tr.c) / 2;
    return sqrt(p * (p - (float)tr.a) * (p - (float)tr.b) * (p - (float)tr.c));
}
void sort_by_area(triangle* tr, int n) {
    for (int i = 0; i < n - 1; i++) 
        for (int j = 0; j < n - i - 1; j++)
            if (getArea(*(tr + j)) > getArea(*(tr + j + 1)))
                swap(tr + j, tr + j + 1);
}