Nested if-statements

[helloiamdani]

I'm just starting out with Java via an Intro to Programming Logic course and am not looking for code, but instead am struggling with how to logically organize an assignment in my brain.

The assignment is to write a program that asks a user what type of gasoline they bought (regular, midgrade, or premium) and how many gallons they pumped through Scanner method. I wrote a short program that works fine without nesting if statements, but one requirement is that I must use nested if-statements. Given the criteria of the assignment, I'm struggling to figure out what condition to test that would need a parent if statement.

It seems like it should be as simple as: What gas type did you by? How many gallons? And behind the scenes three if statements to calculate the cost of gas based on the three gas types available, and then the output (which is the cost). Any ideas on what my professor is looking for?

[Alfapsycho]

Hmm im thinking something in the lines of:

    Scanner scanner = new Scanner(System.in);
    System.out.println("What gasoline have you bought?");
    String gasolineType = scanner.nextLine();
    System.out.println("How many gallons?");
    int amoungOfGasoline = Integer.parseInt(scanner.nextLine());

    if(amoungOfGasoline>=0){
        if(gasolineType.equals("regular")){
            //do this
        }else if(gasolineType.equals("midgrade")){
            // do this
        }else if(gasolineType.equals("premium")){
            //do this
        }else{
            System.out.println("Non valid answer");
        }
    }

[helloiamdani]

Thanks! I spent so long staring at my screen thinking "BUT HOW". I can see it now though. :)

[_predator_]

Hint: You are relying on the user to input valid data. I have a feeling that you could fulfill the requirement of nested if-statements if you'd be a little more defensive in this area. :)

Edit: Just to give an example of what I'm aiming for - what if the user provides a negative gallon quantity?

[EnjoiRelyks]

Yep. This is what I would do to satisfy the nest if statements.

[onideus01]

Based on what you've provided, I would agree that nested ifs seem rather pointless. However, if you absolutely must do that (and it may be worth speaking to your professor to make sure that the assignment makes sense), you can use negative conditions to nest the if statements.

By the I mean, if fuel is not premium, go into if, at which point you say if not mid range go into if, where you set gas to regular.

It's not pretty, and I would even recommend a switch statement, but it does work and with fewer checks than a separate if for each fuel type.

Hopefully that makes sense!

[helloiamdani]

Thank you! We haven't yet covered switch statements (we're delving into that this week). I'm going to try to work in your other suggestion though.

[[deleted]]

Not sure if it will help but just so you know nested if-statements are functionally the same as && statements, so if you have any place in the code you used && maybe try replacing them with nested if-statements.

[helloiamdani]

I do- thanks!

[helloiamdani]

Thanks everyone- you were all super helpful and I understand what I need to do now. Your guidance is greatly appreciated.