Do something if all the criteria are true

Question

In my study I have to program a system that get struct of Apartments that contain: apartment code, price, number of rooms and etc.

In other part of the system when the List of apartments are including apartments, I have to build a function that print out to screen all of the apartments that meet all the requirements the user asking for. for example, for this command from user: "PRINT maxRooms 5 Price 20000" the function will scan the List of apartments and print only the apartments that have maximum 5 rooms and their price is less than 20000.

I've initialize those local variables in -1 and now I'm in the stage that if my local variable different from -1 the user asked for this filter. For the sake of simplicity lets assume that we have only three criteria: price, maximum number of rooms, minimum number of rooms.

I'm trying to avoid this situation:

#define UNDEFINED_FILLTER -1
while (currentAprt != NULL)
        {
            if (maxPrice == UNDEFINED_FILLTER)
            {
                if (MinimumNumOfRooms == UNDEFINED_FILLTER)
                {
                    if (MaximumNumOfRooms == UNDEFINED_FILLTER)
                    {
                        if (1 /*dateofevcation  == undefined*/)
                        {
                            printf("Apartment code: %d\nApartment address: %s\n Apartment price: %d\n", currentAprt->code,currentAprt->address,currentAprt->price);
                            printf("Number of rooms: %d\nPossible entry date: %s\nAdding date: %s",currentAprt->numOfRooms,currentAprt->enteryDate,currentAprt->addingDate);
                        }
                        else
                        {
                            //check date of evacuation criteria
                        }
                    }
                    else
                    {
                        //check maximum number of rooms and date of evacuation criteria
                    }
                }
                else
                {
                    //check minimum number of rooms, maximum number of rooms and date of evacuation criteria
                }
            }
            else
            {
                //check max price, minimum number of rooms, maximum number of rooms and date of evacuation criteria
            }
            currentAprt = currentAprt->next;
        }

MY QUESTION: Is there any simple way to check if the user wrote a command with criteria, check it and go for the next criteria? or the only way is to write it with if-else statements?

Answer 1

I find that many complex if-then trees can be greatly simplified by using early returns / early continue:

#define UNDEFINED_FILLTER -1

void loop_over_rooms() {
    for (; currentAprt != NULL; currentAprt = currentAprt->next) {
        if (maxPrice == UNDEFINED_FILLTER) { continue; }
        if (MinimumNumOfRooms == UNDEFINED_FILLTER) { continue; }
        if (MaximumNumOfRooms == UNDEFINED_FILLTER) { continue; }

        // At this point, we know fields are filled 
        printf(...);             
    }
}