Possible to load array with data file and display in other method?

[Taylor Hall]

I am able to load the entire array (50 different integers), but need to create a seperate method to display only the first 10 numbers....... I have asked a lot of people and nobody seems to have an idea! Please help

/****************************************/

class ArrayDemo {
	public static void main(String[] args) {

		int[] anArray;
		int ageCount = 0;
		int age;
		String filename = "ageData.dat";

		anArray = new int[10];

		try {
			Scanner infile = new Scanner(new FileInputStream(filename));

			while (infile.hasNext()) {
				age = infile.nextInt();

				ageCount += 1;
				System.out.println(ageCount + ".  " + age + "\n");
			}
			infile.close();

		} catch (IOException ex) {
			ageCount = -1;
			ex.printStackTrace();
		}         

	}
}
==================================================================

//   This code displays all of the numbers instead of just the first 10   :-(
AND
I would like to display those first 10 in a seperate method like:

	public void displayTen() {
	for (int tenAge : anArray)
		System.out.printf ("\n", tenAge);
}

could somebody please help, maybe an example of a code that you would use to display numbers 1-50 in a seperarate method?

[Tim Harris]

Include a check for your ageCount in your while loop.

For example while(infile.hasNext && ageCount < 20) would get you the first 20 records (if the infile has that many records).

From there you can put the values in an array (or list, or whatever you choose), and pass that array to a new method when the loop is done.

[Taylor Hall]

How would one display that in a seperate method?

[Tim Harris]

Couldn't edit my post quick enough for your reply:

From there you can put the values in an array (or list, or whatever you choose), and pass that array to a new method when the loop is done.

[Liutauras Vilda]

Hi Taylor,

I've added code tags for you. Please check how to UseCodeTags (<-link) next time.
See how much easier to read your code

edit: also corrected code indentation

[Liutauras Vilda]

Some observations:
You have declared array, but you're not using it in order to store "age's".
What you need to do, is, instead "age = infile.nextInt();" on line 18 or 19 can't see which line it is, you need to store age to an array.

Fix that, then let's see what other problems you still facing.

[Taylor Hall]

well i did so by changing that line to:

anArray[age] = infile.nextInt()

/*********************/

but it tells me i need to initialize it, so if i initialize it by setter age = 0, then when i try to output the array in a different method or even simply placing System.out.print(age) after the try-catch, the output is 0....

Can somebody please show me what a code would look like for a different type of program? That way i can see how an accurate code similar to this one, is supposed to look

[Liutauras Vilda]

well i did so by changing that line to:
anArray[age] = infile.nextInt()

It is not correct. "age" is the variable which holds the value you want to add to an array's certain position. Within brackets needs to be specified position (index) in which you're going to add your element.
Each array element is being accessed by index. If your array can hold 10 elements, it means your array have 10 indices starting from 0 to 9 (inclusive).
So, to add elements to array:

anArray[0] = infile.nextInt(); // adding to 1st position
anArray[1] = infile.nextInt(); // adding to 2nd position
...
anArray[9] = infile.nextInt(); // 10th position, since indices starts from 0

But manually specify positions where you want to add elements wouldn't be best solution.
You need to use "anArray[index]", where index suppose to be incremented every iteration.
An example with "for" loop:

for (int i = 0; i < array.length; i++) {
    array[i] = userInput; // each time "i" changes by accessing next array position
}

The same effect you can achieve with "while" loop by declaring your index variable outside the loop and later by incrementing within the loop body.

[Taylor Hall]

I could not get that to work, i think im confusing myself the more things that i try. This is the code that i have with notes. Somebody....Anybody...

class ArrayDemo {
	public static void main(String[] args) {
	
		int[] anArray;
		int ageCount = 0;
		int age;
		String filename = "ageData.dat";
		
		anArray = new int[50];
		/* The file has 50 numbers which represent an employee's age */
		try {
			Scanner infile = new Scanner(new FileInputStream(filename));

			while (infile.hasNext()) {
				
				age = infile.nextInt();
				ageCount += 1;
				
				System.out.println(ageCount + ". " + age + "\n");
				/* 
				 * When i run just this, the output is correct...
				 * 
				 * But i don't want the output here, i just want to gather 
				 * the information from the file and place it at the bottom inside
				 *  the method displayAges().*/
				 
			}
			
			infile.close();

		} catch (IOException ex) {
			ageCount = -1;
			ex.printStackTrace();
		}
		
		
		public void listOfAges() {
			System.out.print("  I want to display the data gathered from ageData.dat in this method  ");
			System.out.print("  Also, i recieve this error message when i try: 'Illegal modifier for parameter listOfAges; only final is permitted'  ")
		}
  
	
	
	}
}

[fred rosenberger]

I think the problem is that your computer is on. Turn it off. Get some paper and pencils, and start writing out directions to be given to a child. Break it down step by step. When you think you have each step needed, go back and try refining each step into more discrete pieces.

Once you have that done, start coding it in pieces. Remember that the part that prints the array shouldn't care how that array gets populated. So, if you wanted to start with writing the method that prints the first ten elements of an array, build an array by hand with (say) 15 elements. Pass it in to your method, and get JUST THAT METHOD to work. Once you have it working exactly how you want it, THEN you can start writing the code to populate the array in whatever manner you wish.