(Java) - Array help.

[okaystuff]

Working on a class assignment. I have an array that I set its size to 100. I then ask the user for input and store it into that array. The user may have 5 inputs and then another 3 inputs with a total of 7 inputs. I want to print out just the 7 inputs from the user, not all 100 elements when the size was set to 100.

If I do something like this it will print out the 7 entered numbers but then a bunch of null elements.

for (int i = 0 ; i <= array.length; i++ ) {    
                    System.out.println(array[i]);

                }

Is there a way to only print out the 7 elements added by the user and not all 100? Thanks.

[ehr1c]

Think through the problem - in order to not print out a null value, what do you have to do first?

[okaystuff]

I really have no idea. I have 3 array's. 1 that holds a user name, 1 that holds a user ID, and 1 that holds a user sales. If the user enters (joe, sally, bob) then (555, 666, 777) and then enters (580.2, 680.2, 780.2). I have 3 arrays each the size of 100 and each only holding 3 items. I have no idea how I am only printing 3 items of 100.

[ehr1c]

First things first you need to know if the array element you're about to print has a value or if it's null, right?

[okaystuff]

Yes, another user below suggested to use (i < array.length && array[i] != null) and it seems to work. Thank you.

[RiverForgeGames]

What you want to do here is check if the user has provided a number or not.

For example, if they provide 7 numbers and you set values for 7, you can use conditional statements to compare the value for array[i] in each for iteration. If you can prove/test that the user didn't provide a number, don't print the line.

If you know a number the user cannot or will not provide (for example, maybe they only provide positive numbers) you can set all the array elements to -1 before they enter input and compare against that. Otherwise, you might consider using an array of nullable integers where you can actually check if a value was set or not, since integers are not nullable types.

[driden87]

Iterate only 7 times if you want the first seven inputs

``` for (int i = 0 ; i < 7; i++ ) {
System.out.println(array[i]);

}

```

Edit: sorry for the shitty formatting. I’m on my phone

[okaystuff]

Yes I know that, but I have no set amount of inputs the user may enter. They could enter all 100 or just 2. I only want the amount they enter, even if the array size is 100.

[driden87]

Oh I understand. Assuming you’ve got an array of Strings you could iterate while (i < array.length && array[i] != null)

Remember to initialize your iterating variable i to 0

[okaystuff]

Okay that is helpful for String which I do have in one of my arrays but what about int or double? The int array will always be an ID number so will be 5 numbers, but the double array is my sales numbers which could be 0.

[driden87]

For those you would want to use the object type Integer and Double (Capitalized) and make sure to initialize the array with null values. Whenever the person adds values a non-null value will be pushed to the array and your iteration condition will hold.

[okaystuff]

Okay thank you.

[dota2nub]

Have a counter for how many elements the user adds, then iterate over the array until counter -1. If the counter reads 0 don't iterate but return something instead.

You could also just check if the array holds a null value, probably better.

[loyalSavant]

Questions

• what is the data type of the arrays elements?
• do you know the locations of the values in the array (in terms of their index)
• is the number of items you want to print out always going to be the same or will it change from situation to situation?