Array Length?

the length property of an array object is final. How is it then possible to create an array object at run-time and specify the length for the array?
Thanks in advance

public myClass {
public final int myValue;
myClass(int value) {
myValue = value;
//rest of your constructor code...
//rest of your class
The key is you have to set the value of the final 'variable' in your constructor. which means, unless the value is calculated in the constructor, it should be passed to the constructor like:
myClass mc = new myClass(1400);
Steve

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Why arrays length is defined to be a field not a method in Java?

Why arrays length is defined to be a field not a method in Java?

TRANSLATE result USING R.
This statement replaces all characters in field result according to the substitution rule stored in field string R . R contains pairs of letters, where the first letter of each pair is replaced by the second letter.
in your case TRANSLATE result USING '#'.
menas '#' and ' ' space are 2 pair of characters.. and # is replaced by ' ' (space).
for better understanding..
Example:
DATA: T(10) VALUE 'AbCdEfGhIj',
STRING LIKE T,
RULE(20) VALUE 'AxbXCydYEzfZ'.
STRING = T.
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WRITE / STRING.
Output:
xXyYzZGhIj
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How to set array length correctly in this case

class RunJavaCode implements ActionListener{
    public void actionPerformed(ActionEvent e){
      try{
        Process proc=Runtime.getRuntime().exec("java javaapp");
        InputStream input=proc.getInputStream();
        byte[] b=new byte[3000];
        input.read(b);
        String javaReport=new String(b);
        input.close();
        outputText.setText(javaReport);
      }catch(IOException ioex){System.out.println("IOException is "+ioex);}
}how to set this array(byte[] b) length correctly? I mean this array length should not only save memory,but also enough to use('enough to use' mean that read outputed info from console to this byte array never overflow)

Hi,
you cannot know in advance, how many bytes will be read. But the read-method returns the number of bytes actually read and this is important!
So at least you have to write:        int r = input.read(b);
        String javaReport=new String(b, 0, r); However, you still do not know, whether there is even more output available. You could however retrieve the data in a loop and append it e.g. to a StringBuffer, until EOF is encountered.

Maximum array length in javacard

hi all
i have a java class with 20 member variables.
member variables are array of bytes. i doesn't allocate
memory for this variables in class constructor,
memory for this variables is dynamically allocated
in my javacard applet (*runtime*).
i defined an array of this class in my applet( in applet constructor):
myclassArray = new myclass[MAX]
for ( short i =0; i < MAX; i++ )
    myclassArray[i] = new myclass();myclass.java:
       class myclass {
             byte[] membervariable1;
              setVar1( byte[] input) {
               membervariable1 = input;
        }if MAX >= 100 , i can't load applet on the card.
(error :conditions of use not satisfied)
why this problem occurs? my card is 32k and i doesn't allocate memory for myclass member variables in applet constructor;
maybe an array of class in javacard has a maximum value in its length. am i right?
thanks,
siavash

s.fallahdoost wrote:
hi all
i have a java class with 20 member variables.
member variables are array of bytes. i doesn't allocate
memory for this variables in class constructor,It doesn't look like it. If you look at the code snippet below, which is located in the constructor, you are allocating memory in the loop.
memory for this variables is dynamically allocated
in my javacard applet (*runtime*).Does not like it neither. If you look at your second code snippet, you're jusr re-referencing the pointer to another instance.
i defined an array of this class in my applet( in applet constructor):
myclassArray = new myclass[MAX]
for ( short i =0; i < MAX; i++ )
myclassArray[i] = new myclass();myclass.java:
class myclass {
byte[] membervariable1;
setVar1( byte[] input) {
membervariable1 = input;
}if MAX >= 100 , i can't load applet on the card.
(error :conditions of use not satisfied)Could be, since you're allocating memory in the constructor.
why this problem occurs? my card is 32k and i doesn't allocate memory for myclass member variables in applet constructor;
maybe an array of class in javacard has a maximum value in its length. am i right?The maximum array length is 32k.

Problems with getting array length

I couldn't get array length in the java from the oracle.
Here is my source.
Can anybody answer me, I will really appriciate that.
Thanks.
public class Test_tb{
public static double Test (oracle.sql.ARRAY args){
double ret = 0;
try {
Double[] retArr = (Double[]) args.getArray();
return retArr.length;
} catch (Exception e){}
return ret;
}

I've rewritten your code to include the display of any exception that might occur. Could you please run it and post any stack trace here? Thanks.
public class Test_tb{
public static double Test (oracle.sql.ARRAY args){
double ret = 0;
try {
    Double[] retArr = (Double[]) args.getArray();
    return retArr.length;
} catch (Exception e){}
    e.printStackTrace();
    return ret;
}

Question on array.Length

I have an array[4]. Then the subscripts are number 0, 1, 2, 3. Does array.Length return 4 or 3. I am thinking 4 but I want to make sure.

java.secure(?).SecureRandom.java.security.SecureRandom
It's more straightforward and has better statistical properties.While I agree, with the straightforward,
but statistical I would of thought they'd
be even.It's better for several reasons:
1) nextInt is faster. It uses (on average) 1-1/3 calls to next(int), whereas nextDouble() (what Math.random() uses) always uses two. This also means nextInt will use up the generator's period more slowly.
2) It's statistically better. Although the odds of you noticing that some numbers are favored (slightly) over the "noise" of the prng's own bias are negligible.
3) It's nicer to use nextInt. It uses OO (instead of the relatively global function call to Math.random()), it doesn't compete with other parts of the Application for using up some of the prng's period, it allows the substitution of other (better or worse) algorithms with fewer changes, and it looks better.
~Cheers

How to calc array length in Labwindows CVI ?

How to calc array length in Labwindows CVI ? In labwiew,I can find function to calc array length,but in CVI ,I can not ,...

Hello 让一切随风
char *name ;
int length = 0;
int i = 0;
name = malloc(256) ;
strcpy(name , "National Instruments");
while( name[i] ! = "\0")
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i++
free(name);

Finding Array Length

I was just wondering if i have an array
double [][][] array = new double [1][2][3];array.length only gives 1, what function can i use to find the size of the other dimensions (2 and 3)? Thanks in advance for any help.

I'll try and explain this a little better.
Say array[0].length is 2, then that means that there is only
array[0][0] and array[0][1].
If array[0][0] is 4, then that means that there is only
array[0][0][0], array[0][0][1], array[0][0][2], and array[0][0][3].
The reason i did array[0][0].length and not array[0][1].length
in my other post is because they would both return the same
thing because of the way you declared the array.
When you dodouble[][] array = new double[2][3];this is making it so that array[0].length is 3 and array[1].length is 3.
But if you do this (shown in the previous post)
double[][] aray = {
{ 2.4, 5.6, 6.4 },
{ 1.4 }
}then array[0].length is 3, but array[1].length is 1.
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This and super keywords, array.length attribute

'this' and 'super' keywords and array.length attribute are declared in which java class?
and also during running of a java program how they are initialized and how they work?

'this' and 'super' keywords and array.length attribute are declared in which java class?They are not declared in any Java class, any more than the keywords 'class', 'interface', 'for', 'while', etc., are. They are defined in the grammar of the Java language, in the Java Language Specification.
and also during running of a java program how they are initialized and how they work?That's much too large a question for a forum. Try reading the Java Tutorial.

Maximum possible ARRAY LENGTH ?!?!

Hello All
How can I know (before allocating memory) what is the maximum possible array length. Does it depend on the JVM version or OS or something else ???
Please help !

Thanx All !!!
I've moved to more "memory saving" algorithm, so there is no problem now :-))
But another 2 questions has poped up: I'm using a Vector object in a pretty long loop (millions of iterations) and once in a while accumulating some data (Long and Double objects) by adding them to the Vector.
1. What can be the maximum possible vector length ?
2. What's faster: using a Vector object or using a regular "long or double" array that should be reallocated as:
double[] arr = new double[****];
for(long i=0; i<Long.MAX_VALUE; i++)
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Quick array length question...

for this part of my code i'm trying to determine the components needed to find the average of my array. I can't seem to find a way to determine the length of my array (how many components it consists of). Every time I keep getting the dereferencing error....I know it's something simple but I just can't seem to get it right. Please help!
int total = 0, mean = 0, length = 0;
for(int j=0; j<i; j++)
total = total + array[j];
System.out.print(array[j]+" ");
System.out.print(total);

Hi Cher,
This length attribute if any array object will give you the number of components I mean number of elements in that array.
array.length; rather than array.length();
This may be helpfull.
int total = 0, mean = 0, length = 0;
for(int j=0; j<array.length; j++)
total = total + array[j];
System.out.print(array[j]+" ");
System.out.print(total);>
Aski

Get Type ArrayElement fails if array length is 0

All:
Get<Type>ArrayElement fails if the array length is 0 in 1.4. It seems to work fine in 1.5. I was "googling" and I found this link -- http://e-docs.bea.com/wljrockit/v315/relnotes/relnotes.htm. It mentions that this problem -- The JNI methods GetStringChars and Get<>ArrayElements threw OutOfMemoryError if called with a String or array of zero length -- was fixed in version 3.1.4. What is version 3.1.4 and how does this relate to JDK verions that I get out of java -version.
I will appreciate any pointers.
M.P. Ardhanareeswaran
Oracle USA

Drag and drop within a datagrid is rather an unusual thing to do.
I would suggest your problem lies in choosing to do something which will cause complications.
Hope that helps.
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String array length

Can any one tell me how to get the no. of rows and no. of columns in an string array.
ie if i have array like
1 2 3 4
4 5 6 5
7 8 9 6
in an a[][]. how to fine values ie row =3 and col = 4

Assuming that the array is a rectangle (all rows have the same number of columns) and that it's two dimensional, you can do this:
int row = a.length;
int col=a[0].length;
I think that works, try it

Passing Array to Alchemy, Array.length

Hi,
Trying to pass an Array to alchemy. Works great, but...
How to determine length of the array?
My code (ahum :-) thus far:
static AS3_Val test(void* self, AS3_Val args)
AS3_Val dataVal = AS3_Undefined();
AS3_ArrayValue( args, "AS3ValType", &dataVal );
// trace out array[0]
AS3_Trace( AS3_Get(dataVal, AS3_Int(0) );
return AS3_Null();
Thanks,
Tim

To answer my own :
1] maybe smarter to pass length of array too :-)
2] do a loop:
int len = 0;
while( AS3_Get(arrayVal, AS3_Int(len++)) )
Guess this is _not_ the way to do it, but at least seems to
work

Array.length Question

Hello,
I am trying to find out what class array's length attribute comes from and how array is able to use it.
I have been studying the API but cannot find it or work it out.
Thanks,
Harold Clements

Arrays are considered part of the language and are not listed in the API.
But length appears to behave like a public field, mostly.
Have you checked the language spec? It's available free online.

Array Length?

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