carpet_quote.c

float area(const struct Room *room) {
    return room->length * room->width;
}

float price(const struct Carpet *carpet, float area) {
    if(carpet->roundUp){
        area = ceil(area);
    }

    return area * carpet->pricePerSqrMetre;
}

float quote(struct Room *room, struct Carpet *carpet){
    return price(carpet, area(room));
}