[SOLVED] Need help with Java application

[jhrh95]

I'm new to Java (only a few weeks under my belt) and struggling with an application. The project is to write an app that inputs 5 numbers between 10 and 100, not allowing duplicates, and displaying each correct number entered, using the smallest possible array to solve the problem. Output example:

Please enter a number: 45
Number stored.
45
Please enter a number: 54
Number stored.
45 54
Please enter a number: 33
Number stored.
45 54 33

etc.

I've been working on this project for days, re-read the book chapter multiple times (unfortunately, the book doesn't have this type of problem as an example to steer you in the relatively general direction) and am proud that I've gotten this far. My problems are 1) I can only get one item number to input rather than a running list of the 5 values, 2) I can't figure out how to check for duplicate numbers. Any help is appreciated.

My code is as follows:

import java.util.Scanner; // program uses class Scanner

public class Array
{

public static void main( String args[] )
{
// create Scanner to obtain input from command window
Scanner input = new Scanner( System.in);

// declare variables
int array[] = new int[ 5 ]; // declare array named array
int inputNumbers = 0; // numbers entered


while( inputNumbers < array.length )
{

// prompt for user to input a number
System.out.print( "Please enter a number: " );
int numberInput = input.nextInt();

// validate the input
if (numberInput >=10 && numberInput <=100)
System.out.println("Number stored.");
else
System.out.println("Invalid number. Please enter a number within range.");

// checks to see if this number already exists
boolean number = false;

// display array values
for ( int counter = 0; counter < array.length; counter++ )
array[ counter ] = numberInput;

// display array values
System.out.printf( "%d\n", array[ inputNumbers ] );

// increment number of entered numbers
inputNumbers++;
}
}

} // end close Array

[Eranga]

Do not use the class name Array here. It's a standard API class name.

[jhrh95]

I actually hadn't in my app. I'd used a pretty long name, so I'd just changed it to "Array" when I posted it since it was shorter. Good point, thought. Thx.

[Eranga]

Here is one simple logic to do this comparison. Once you read a value from the user, compare it with the whole array. It's easy since you have a counter. Here in addition I use a label to skip the rest of the process.

public class CollectUserData {

    public static void main( String args[] ) {

        // create Scanner to obtain input from command window
        Scanner input = new Scanner( System.in);

        // declare variables
        int array[] = new int[ 5 ]; // declare array named array
        int inputNumbers = 0; // numbers entered

        outer:
        while( inputNumbers < array.length ) {
            // prompt for user to input a number
            System.out.println( "Please enter a number: " );
            int numberInput = input.nextInt();

            // Check for duplicate
            for(int i = 0; i < array.length; i++) {
                if(array[i] == numberInput) {
                    System.out.println("Duplicate number is found");
                    continue outer;
                }
            }
            
            // validate the input
            if (numberInput >=10 && numberInput <=100) {
                System.out.println("Number stored.");
                array[inputNumbers] = numberInput;
            }
            else {
                System.out.println("Invalid number. Please enter a number within range.");
            }
            
            // display array values
            for(int val = 0; val <= inputNumbers; val++) {
                System.out.print(array[val] + " ");
            }

            // increment number of entered numbers
            inputNumbers++;
        }
    }
}

[CJSLMAN]

jhrh95:
Suggestion on your coding style... always use curly brackets "{}" with your if, else and for statements, even if it's a one liner. This way you can add lines of code without any problems and save yourself head aches later on.

Luck,
CJSL

[Eranga]

And also commenting the code. It's better if you can keep them much shorter with clearly descriptive.

At the same time, please use CODE tags when you post code segments again here in the community.

[jhrh95]

I tried to do that, but it didn't take. Sorry! I didn't mean to make it difficult to read. Thank you so much for pointing me in the right direction. In reviewing the changes you made, I wasn't as far off as I thought I was... it looks like I was just missing pieces. I modified the changes you gave me so that it also doesn't show a 0 value for numbers entered outside of the range (<10 && >100). Thank you again for your guidance.

[jhrh95]

Thanks for the feedback.

[jhrh95]

For my own knowledge, how could I have made it work without using 'outer', and 'continue outer'? My understanding of Java (again, please remember, I'm a beginner) is they refer to nested classes and it's referring to an outer public class. Right? But that shouldn't be required to make the correct values show. I've been playing around with the code trying to understand it better. Rather than outer / continue outer, I tried another while statement to force a loop. It worked except that it now allows 0's to show if the input numbers were outside the specified range (<10 and > 100) and it also allowed duplicates to appear. :(

[CJSLMAN]

... they refer to nested classes and it's referring to an outer public class. Right?

Wrong... you only have one class: CollectUserData. "outer" is a label and is generally asociated with the "goto" statement. It can also be used effectivaly with branching statements. See the following link:
Branching Statements (The Java™ Tutorials > Learning the Java Language > Language Basics)

Luck,
CJSL

[Eranga]

I tried to do that, but it didn't take. Sorry! I didn't mean to make it difficult to read. Thank you so much for pointing me in the right direction. In reviewing the changes you made, I wasn't as far off as I thought I was... it looks like I was just missing pieces. I modified the changes you gave me so that it also doesn't show a 0 value for numbers entered outside of the range (<10 && >100). Thank you again for your guidance.

What you mean 0 values. In your application value zero also excepted in the following line of code.

if (numberInput >=10 && numberInput <=100) {

That's your implementation.

[jhrh95]

I wanted the results to show unique numbers with no 0's (i.e., 34 54 67 45 23). However, when I input a number < 10 (i.e., 4) or > 100 (i.e., 3223), or a duplicate number, it would store a 0 in the results rather then ignoring the value. For example, if I entered 344 rather than 34 from the set of numbers I'd given above, the results would have shown as 0 54 67 45 23). Does that better clarify what I was trying to say?

[Fubarable]

You may want to post your latest code effort, but if you do, only post code related to this problem, and it would help us immensely if this code is compilable. This is called an SSCCE, and you can read more about creating this here: SSCCE.org

[Eranga]

You have given lots of hints here. Read them and try to workout it first as Fubarable says.

Think a way to check that input number is not equal to zero.

[jhrh95]

Yes, it's working just fine. Thanks to all for your help. I had just wanted to clarify that I'd made more changes on my own and it worked great.

[Eranga]

The best thing is when you ask a question show your effort as well, post code segment to clearly say what you have done.

Anyway, if you have solve the problem please mark it as solved.

[jhrh95]

How do I mark it solved? I checked the FAQ/Bulletin FAQ but couldn't find anything to tell me how.