Need to iterate through two arrays of items for comparison without parallelism

Question

So for my java class I have to write a program that accepts toppings and adds 75 cents to total price for every topping. I haven't bothered for null testing yet because of this error. Essentially I will have:

list1 = Valid Toppings
list2 = User Toppings

User toppings can be entered in any order so it doesn't make any sense to match them as a parallel array. You can see the logic I have used in the code snippet below, but it is not legal. My terminal vomits everywhere when I try to compile. How would I go about implementing the logic below, or perhaps a better way of implementing my logic completely?

  for(x = 0; toppings.length < 3; x++)
    {
      if(toppings[x].equals(for(xx = 0; validToppings[0].length < 3; xx++) {validToppings[xx]})
        {setSize(size); price += .75;}
        else
        {System.out.println("Error in Pizza class: Attempt to set invalid pizza topping" + x + "(" + toppings[x] + ")")};
    }

Answer 1

The problem here is you are trying to use an if statement, which does a single boolean comparison, to a for statement, which can not be made into a boolean.

Do it like this instead:

for(int x = 0; topping.length < 3; x++){
         for(int xx = 0; vaildToppings[0].length < 3; xx++){
             if(toppings[x].equals(validToppings[xx]){
//do stuff
     }
}

Nested for loops are your friend.

topping.length < 3 as your conditions to close is also non nonsensical. Consider reexamining your logic, I don't know what you are actually trying to do, so I'm not going to make any assumptions.

Answer 2

The reason your code is breaking is because you have toppings.length < 3 and validToppings[0].length < 3 when you want, presumably, x < 3 or x < toppings.length

Everything in your for loop should be based on your counter.

Answer 3

Try this:

for (int x = 0; x < toppings.length; x++)
{
    if (!validToppings.contains(toppings[x]))
    {
        //throw some error, or print a message, etc....
    }
    else
    {
        //do stuff
    }
}

Answer 4

A nested for-loop is the right approach here. Don't forget to declare the type of your loop counter in the loop itself (or elsewhere, if you want to use C style), or you'll get compiler errors all day.

for(int x = 0; x < toppings.length; x++) {
    for(int xx = 0; xx < validToppings[0].length; xx++) {
        if(toppings[x].equals(validToppings[xx]) {
            // Perform operations here.
    }
}

As a side note: toppings.length < 3 may or may not be true throughout the loop; it could never be true, thus causing the loop not to execute, or it could be true, causing an infinite loop, regardless of x or xx . Be careful for cases like that.

Answer 5

I'm not sure what you're trying to do. If you are trying to test whether one array of strings is in another array of strings, (as in, a 'subset' in Set Theory). Then why not use ArrayList , something like this: (sorry if my syntax is a little off it's been a while since I did java)

ArrayList<String> toppings = new ArrayList<>();
toppings.add("Pepperoni");
toppings.add("Olives");

ArrayList<String> validToppings = new ArrayList<>();
validToppings.add("Pepperoni");
validToppings.add("Salami");
validToppings.add("Olives");
validToppings.add("Cheese");

boolean toppingsValid = validToppings.containsAll(toppings);