Thread: Array and loops.

Hello guys,
So I decided to experiment with what I know.
Start out with a small program then build on it till I used everything I know, with out making any mess.
I came up with an idea of a program that will tell me who's birthday it is and how many days are left for the other peoples birthdays (I used 7 people).

class BirthdaySurprise {
    public static void main(String[] args){
        // here are all the people
        byte TSE = 122;
        short LA = 184;
        short ZE = 195;
        short AB = 199;
        int DE = 234;
        int HA = 349;
        int AL = 361;
        //That's the last one. The numbers are the number of the day that 
        //each person's birthday comes on. So if your birthday comes on Jan 1 
        //your variable will be equal to 1, and if on Dec31 it will be equal to 365.   
        for( byte aryOneAdder = 1; aryOneAdder <121;){
            //Now what I want to happen here is the for loop increments aryOneAdder
            //till it's equal too 121. And store all the numbers in the aryOne array
             aryOneAdder++;
             byte[] aryOne = new byte[aryOneAdder];
             System.out.println(aryOne[0]);
        }
 
    }
}

Output:
run:
0
0
0
0
0
0
0
0
0
0
0( 121 zero's in all )

What went wrong in that loop?

Oh and the aryOne array is made in the for loop, that means I wont be able to use it out of the loop right?

byte[] aryOne = new byte[aryOneAdder]; // Create a new byte array with aryOneAdder elements

Your loop creates a new array every time it loops. That replaces the one that was created on the last loop

store all the numbers in the aryOne array

To do that create the array of the size you want, OUTSIDE the loop and then in the loop assign each value to an element of the array:
aryOne[aryOneAddr] = aryOneAddr; // assign value to array element: value equals the index

( 121 zero's in all

The default value for an int array element is 0

Any clue to what woke up indexOutOfBounds?

There is important info in the error message, please copy and paste here the full text of the message.

It looks like you create the array AFTER you try to use it.
Create the array BEFORE you use it.

After turning of the pc for a few hours and trying again oddly the output has changed.
Output:

run:
0
BUILD SUCCESSFUL (total time: 1 second)

Even before changing the place of the array.

Magic. Or you've got a ghost changing your program.

My guess: last time a virus messed up Netbeans I uninstalled it and re-downloaded it, but looks like some crazy files where left behind somewhere. :/ I'm planing on uninstalling all programs and downloading them again, might be the registry playing games on me but lets not hope its that.

Anyway it still prints out 0, and not 1-121, you know why?

P.S. If you know any program that can fix the registry leave a link plz.

Thanks! That sure is a different way of looking at it!

Should I find something strange in the output of

byte aryOneAdder;
        byte[] aryOne = new byte[123];
        for(aryOneAdder = 1; aryOneAdder <121;){
            //Now what I want to happen here is the for loop increments aryOneAdder
            //till it's equal too 121. And store all the numbers in the aryOne array
             aryOneAdder++;   
             aryOne[0] = aryOne[aryOneAdder];
        }        
 
        System.out.println(aryOne[0]);

and

for(aryOneAdder = 1; aryOneAdder <121;){
            //Now what I want to happen here is the for loop increments aryOneAdder
            //till it's equal too 121. And store all the numbers in the aryOne array
             aryOneAdder++;   
             aryOne[aryOneAdder] = aryOne[0];
        }        
 
        System.out.println(aryOne[0]);]

and

byte aryOneAdder;
        byte[] aryOne = new byte[123];
        for(aryOneAdder = 1; aryOneAdder <121;){
            //Now what I want to happen here is the for loop increments aryOneAdder
            //till it's equal too 121. And store all the numbers in the aryOne array
             aryOneAdder++;          
        }        
        aryOne[aryOneAdder] = aryOneAdder;
        System.out.println(aryOne[0]);

all being

run:
0
BUILD SUCCESSFUL (total time: 1 second).

I have under-looked something or Kaspersky needs reinstalling.

To see what is in the array after your code executes use this:

System.out.println(Arrays.toString(aryOne)); // Show array's contents

class BirthdaySurprise {
    public static void main(String[] args){
        // here are all the people
        byte TSE = 122;
        short LA = 184;
        short ZE = 195;
        short AB = 199;
        int DE = 234;
        int HA = 349;
        int AL = 361;
        //That's the last one. The numbers are the number of the day that 
        //each person's birthday comes on. So if your birthday comes on Jan 1 
        //your variable will be equal to 1, and if on Dec31 it will be equal to 365.
        byte aryOneAdder;
        byte[] aryOne = new byte[123];
        for(aryOneAdder = 1; aryOneAdder <121;){
            //Now what I want to happen here is the for loop increments aryOneAdder
            //till it's equal too 121. And store all the numbers in the aryOne array
             aryOneAdder++;   
             aryOne[0] = aryOne[aryOneAdder];             
        }      
        System.out.println(Array.toString(aryOne)); // Show array's contents
    }
}

output:
run:
Exception in thread "main" java.lang.RuntimeException: Uncompilable source code
at BirthdaySurprise.main(BirthdaySurprise.java:21)
Java Result: 1
BUILD SUCCESSFUL (total time: 1 second)


Output with the print line statement in the loop:

run:
Exception in thread "main" java.lang.RuntimeException: Uncompilable source code
at BirthdaySurprise.main(BirthdaySurprise.java:21)
Java Result: 1
BUILD SUCCESSFUL (total time: 2 seconds)

What source line is at line 21?
What import statements do you have in your program?
You need to import the package that the Arrays class is in?

Originally Posted by Melawe

What is the import statement I should use?

I assume you wish to use the Arrays (Java Platform SE 6) class and not Array class...see the package name in the link

import java.util.Arrays;

import java.util.Arrays;
class BirthdaySurprise {
    public static void main(String[] args){
        // here are all the people
        byte TSE = 122;
        short LA = 184;
        short ZE = 195;
        short AB = 199;
        int DE = 234;
        int HA = 349;
        int AL = 361;
        //That's the last one. The numbers are the number of the day that 
        //each person's birthday comes on. So if your birthday comes on Jan 1 
        //your variable will be equal to 1, and if on Dec31 it will be equal to 365.
        byte aryOneAdder;
        byte[] aryOne = new byte[123];
        for(aryOneAdder = 1; aryOneAdder <121;){
            //Now what I want to happen here is the for loop increments aryOneAdder
            //till it's equal too 121. And store all the numbers in the aryOne array
            aryOneAdder++;
            aryOne[aryOneAdder] = aryOne[1];
        }      
        System.out.println(Arrays.toString(aryOne)); // line 23
    }
}

Output
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, ] all zeros :/

Sorry for my late late reply.

aryOne[aryOneAdder] = aryOne[1];

What is the contents of: aryOne[1] ?
You are copying it into all of the elements of the array?
If it contains 0 then your program is working as I'd expect it to.

All elements of aryOne are equal to 0.

Ok. Is your problem solved now?

??? The last post showed that the output was the numbers from 1 to 121

That was the output for the Paster program, which I was using to experiment with. But the Birthday Surprise program still has 0 as the output.