declaration of arrays

[noobplus]

hi, I want to initialise the array 'x' in a class which displays the values of 'x'
but where should we declare the array 'x'
I declared inside the public class , but shows errors

public class array_inc {

	
	public static int[] x;
	x=new int[10];
	
	
	public static void main(String args[])
	{for(int i=0;i<10;i++){
		x[i] = i;
		System.out.println(x[i]);
	}
		
	}
}

thx
dhilip

[Tolls]

x=new int[10];

Lines of code like that cannot exist outside of an executable block.
The 'new int[10]' part can be part of the declaration line, though.

[noobplus]

x=new int[10];

Lines of code like that cannot exist outside of an executable block.
The 'new int[10]' part can be part of the declaration line, though.

Ive changed the 'static' to non-static, and accessed it through an object.
is that possible?

public class fileread {

	
	int[] x;//shows an error yet. i get a thought, that i can't declare a variable outside a method
	x=new int[10];
	
	
	public static void main(String args[])
	{
		fileread a = new fileread();
		
	for(int i=0;i<10;i++){
		a.x[i] = i;
		System.out.println(a.x[i]);
	}
		
	}
}

thx
dhilip

[Tolls]

The problem is nothing to do with static or non-static, it is to do with your assignment on line 5.
That code is not allowed outside a block (eg a method).
You can, as I said in my previous post, do the assignment on the same line as the declaration, on line 4.

ETA: You have no, of course, introduced a problem by removing the static from 'x'.

[noobplus]

The problem is nothing to do with static or non-static, it is to do with your assignment on line 5.
That code is not allowed outside a block (eg a method).
You can, as I said in my previous post, do the assignment on the same line as the declaration, on line 4.

ETA: You have no, of course, introduced a problem by removing the static from 'x'.

thx, I've declared it in main, and shows no errors..
what means "ETA", and
what about a constructor,
[code]
public class fileread {

private int[] x;
void fileread()
{
int[] x = new int[10];//ive initializes x, will it be initialized into its object?
}


public static void main(String args[])
{
fileread a = new fileread();

for(int i=0;i<10;i++){
a.x[i] = i;
System.out.println(a.x[i]);
}

}
}
/[code]

thx
dhilip

[Tolls]

ETA = Edited To Add.

You're flailing now.
Look, go back to your original code in your first post.

Now, repeating myself -
"The 'new int[10]' part can be part of the declaration line, though."
That is, the 'new int[10]' on line 5 should be on line 4.
That's it.
That's all you had to do to fix the problem.

[MonkeyMan]

Take your code in post 1 and do this, as Tolls has been saying:

public static int[] x = new int[10];

-Assignments of values have to be inside code block like method
-Declarations can be outside of method blocks
-Combine assignment with declaration

=

problem solved?

Correct me if I'm wrong Tolls, thank you :)

[Tolls]

That's the idea.

[noobplus]

Take your code in post 1 and do this, as Tolls has been saying:

public static int[] x = new int[10];

-Assignments of values have to be inside code block like method
-Declarations can be outside of method blocks
-Combine assignment with declaration



problem solved?

Correct me if I'm wrong Tolls, thank you :)

thank you, problem solved , and working on that..

regards
dhilip

[noobplus]

That's the idea.

thx.. working on that..

regards
dhilip

[noobplus]

public void setData(int i,double x,double y)
	{
		if(i>this.Size)
			return;
		xArray[i]=x;
		yArray[i]=y;
	}

what does the "this.SIZE" and "return;"do ?
(I have a constructor

public ReadPlat(int size)
	{
		this.Size=size;
		xArray= new double[this.Size];
		yArray= new double[this.Size];
	}

and the two variables "xArray" and "yArray" are declared in the main class)

thx
dhilip

[Tolls]

You probably need to go through the tutorials.
This is not just basic stuff, but fundamental.

[noobplus]

You probably need to go through the tutorials.
This is not just basic stuff, but fundamental.

thx , working on that

[noobplus]

import java.io.*;

public class ReadPlat 
{
	double[] xArray ;
	double[] yArray ;
	int Size;
	
	public ReadPlat(int size)
	{
		this.Size=size;
		xArray= new double[this.Size];
		yArray= new double[this.Size];
	}
	
	public void setData(int i,double x,double y)
	{
		if(i>this.Size)
			return;
		xArray[i]=x;
		yArray[i]=y;
	}
	
	public static void main(String[] args) throws Exception
	{   
		ReadPlat ReadPlatInstance;
		String filename;
		FileReader file_in;
		BufferedReader in;	
		String input_line;
		String[]input_split;
		int TotalLineCount=0;
		
		filename = args[0];
		file_in = new FileReader(filename);
	    in 		= new BufferedReader(file_in);
	    
	    input_line ="Starting";
	    
	    
	    //Reading toatal lines 
	    while(input_line!=null)
	    {	
	    	input_line =in.readLine();
	    	TotalLineCount++;
	    }
	    System.out.println(TotalLineCount);
	    ReadPlatInstance = new  ReadPlat(TotalLineCount);
	    
	    //Closing the File and reopening
	    TotalLineCount=0;
	    input_line ="ReStarting";
	    in.close();
	    file_in.close();
	    file_in = new FileReader(filename);
	    in 		= new BufferedReader(file_in);	    
	    while(input_line!=null)
	    {	
	    	 System.out.println("---------------");
	    	 System.out.println("Line No:"+TotalLineCount);
	    	
	    	
	    	input_line =in.readLine();
	    	input_line=input_line.replaceAll("\"","");
	    	input_split = input_line.split(" ");    	   	
	    	
	    	 System.out.println("Input Line:"+input_line);
	    	 System.out.print(input_split.length);
	    	 System.out.print("x"+input_split[0]);
	    	 System.out.print("y"+input_split[2]);
	    	ReadPlatInstance.setData(TotalLineCount, Double.valueOf(input_split[0].trim()).doubleValue(),Double.valueOf(input_split[2].trim()).doubleValue()   )	;    	
	    	TotalLineCount++;
	    	
	    }	
	    
	    in.close();
	    file_in.close();
	    
	    
	}
	
}

I'm getting a run-time error
"Exception in thread "main" java.lang.NullPointerException
at ReadPlat.main(ReadPlat.java:65)"
Could I know why it comes?

--edited: im attaching the argument file.. abc.txt
the text file containing the following values..
"0.000000" " -0.012"
"0.000010" " +0.053"
"0.000020" " +0.050"
"0.000030" " +0.053"
"0.000040" " +0.050"
"0.000050" " +0.053"
"0.000060" " +0.053"
"0.000070" " +0.050"
"0.000080" " +0.053"
"0.000090" " +0.053"
"0.000100" " +0.053"
"0.000110" " +0.053"
"0.000120" " +0.053"
"0.000130" " +0.053"
"0.000140" " +0.053"

regards
dhilip

[noobplus]

import java.io.*;

public class ReadPlat 
{
	double[] xArray ;
	double[] yArray ;
	int Size;
	
	public ReadPlat(int size)
	{
		this.Size=size;
		xArray= new double[this.Size];
		yArray= new double[this.Size];
	}
	
	public void setData(int i,double x,double y)
	{
		if(i>this.Size)
			return;
		xArray[i]=x;
		yArray[i]=y;
	}
	
	public static void main(String[] args) throws Exception
	{   
		ReadPlat ReadPlatInstance;
		String filename;
		FileReader file_in;
		BufferedReader in;	
		String input_line;
		String[]input_split;
		int TotalLineCount=0;
		
		filename = args[0];
		file_in = new FileReader(filename);
	    in 		= new BufferedReader(file_in);
	    
	    input_line ="Starting";
	    
	    
	    //Reading toatal lines 
	    while(input_line!=null)
	    {	
	    	input_line =in.readLine();
	    	TotalLineCount++;
	    }
	    System.out.println(TotalLineCount);
	    ReadPlatInstance = new  ReadPlat(TotalLineCount);
	    
	    //Closing the File and reopening
	    TotalLineCount=0;
	    input_line ="ReStarting";
	    in.close();
	    file_in.close();
	    file_in = new FileReader(filename);
	    in 		= new BufferedReader(file_in);	    
	    while(input_line!=null)
	    {	
	    	 System.out.println("---------------");
	    	 System.out.println("Line No:"+TotalLineCount);
	    	
	    	
	    	input_line =in.readLine();
	    	input_line=input_line.replaceAll("\"","");
	    	input_split = input_line.split(" ");    	   	
	    	
	    	 System.out.println("Input Line:"+input_line);
	    	 System.out.print(input_split.length);
	    	 System.out.print("x"+input_split[0]);
	    	 System.out.print("y"+input_split[2]);
	    	ReadPlatInstance.setData(TotalLineCount, Double.valueOf(input_split[0].trim()).doubleValue(),Double.valueOf(input_split[2].trim()).doubleValue()   )	;    	
	    	TotalLineCount++;
	    	
	    }	
	    
	    in.close();
	    file_in.close();
	    
	    
	}
	
}

I'm getting a run-time error
"Exception in thread "main" java.lang.NullPointerException
at ReadPlat.main(ReadPlat.java:65)"
Could I know why it comes?

--edited: im attaching the argument file.. abc.txt
the text file containing the following values..
"0.000000" " -0.012"
"0.000010" " +0.053"
"0.000020" " +0.050"
"0.000030" " +0.053"
"0.000040" " +0.050"
"0.000050" " +0.053"
"0.000060" " +0.053"
"0.000070" " +0.050"
"0.000080" " +0.053"
"0.000090" " +0.053"
"0.000100" " +0.053"
"0.000110" " +0.053"
"0.000120" " +0.053"
"0.000130" " +0.053"
"0.000140" " +0.053"

regards
dhilip

problem solved.. I restarted my eclipse, now it's working fine without run time errors.
thx
dhilip

[noobplus]

import java.io.*;

public class ReadPlat 
{
	double[] xArray ;
	double[] yArray ;
	int Size;
	
	public ReadPlat(int size)
	{
		this.Size=size;
		xArray= new double[this.Size];
		yArray= new double[this.Size];
	}
	
	public void setData(int i,double x,double y)
	{
		if(i>this.Size)
			return;
		xArray[i]=x;
		yArray[i]=y;
	}
	
	public static void main(String[] args) throws Exception
	{   
		ReadPlat ReadPlatInstance;
		String filename;
		FileReader file_in;
		BufferedReader in;	
		String input_line;
		String[]input_split;
		int TotalLineCount=0;
		
		filename = args[0];
		file_in = new FileReader(filename);
	    in 		= new BufferedReader(file_in);
	    
	    input_line ="Starting";
	    
	    
	    //Reading toatal lines 
	    while(input_line!=null)
	    {	
	    	input_line =in.readLine();
	    	TotalLineCount++;
	    }
	    System.out.println(TotalLineCount);
	    ReadPlatInstance = new  ReadPlat(TotalLineCount);
	    
	    //Closing the File and reopening
	    TotalLineCount=0;
	    input_line ="ReStarting";
	    in.close();
	    file_in.close();
	    file_in = new FileReader(filename);
	    in 		= new BufferedReader(file_in);	    
	    while(input_line!=null)
	    {	
	    	 System.out.println("---------------");
	    	 System.out.println("Line No:"+TotalLineCount);
	    	
	    	
	    	input_line =in.readLine();
	    	input_line=input_line.replaceAll("\"","");
	    	input_split = input_line.split(" ");    	   	
	    	
	    	 System.out.println("Input Line:"+input_line);
	    	 System.out.print(input_split.length);
	    	 System.out.print("x"+input_split[0]);
	    	 System.out.print("y"+input_split[2]);
	    	ReadPlatInstance.setData(TotalLineCount, Double.valueOf(input_split[0].trim()).doubleValue(),Double.valueOf(input_split[2].trim()).doubleValue()   )	;    	
	    	TotalLineCount++;
	    	
	    }	
	    
	    in.close();
	    file_in.close();
	    
	    
	}
	
}

I'm getting a run-time error
"Exception in thread "main" java.lang.NullPointerException
at ReadPlat.main(ReadPlat.java:65)"
Could I know why it comes?

--edited: im attaching the argument file.. abc.txt
the text file containing the following values..
"0.000000" " -0.012"
"0.000010" " +0.053"
"0.000020" " +0.050"
"0.000030" " +0.053"
"0.000040" " +0.050"
"0.000050" " +0.053"
"0.000060" " +0.053"
"0.000070" " +0.050"
"0.000080" " +0.053"
"0.000090" " +0.053"
"0.000100" " +0.053"
"0.000110" " +0.053"
"0.000120" " +0.053"
"0.000130" " +0.053"
"0.000140" " +0.053"

regards
dhilip

hi,
I want to write to create a calculation on the arrays "xAary" and yArray" values.. so, where should I write it?
inside main(at line 73) ? or as a different method(before main)?