asked on

ArrayIndexOutOfBoundsException

//Program: Line and letter count

import java.io.*;

public class CharacterCount
{
public static void main(String[] args)
throws FileNotFoundException, IOException
{
int lineCount = 0;
int[] letterCount = new int[26];

IntClass next = new IntClass();

FileReader inputStream = new FileReader("F:\\text.txt");
PrintWriter outfile =
new PrintWriter(new FileWriter("F:\\textCh.out"));

next.setNum(inputStream.read());

while(next.getNum() != -1)
{
copyText(inputStream, outfile, next, letterCount);
lineCount++;
next.setNum(inputStream.read());
} // end while loop

writeTotal(outfile,lineCount,letterCount);

outfile.close();
}

static void copyText(FileReader infile, PrintWriter outfile,
IntClass next, int[] letterC) throws IOException
{
while(next.getNum() != (int)'\n')
{
outfile.print((char)(next.getNum()));
chCount((char)(next.getNum()), letterC);
next.setNum(infile.read());
}
outfile.println();
}

static void chCount(char ch, int[] letterC)
{
int index;
int i;

ch = Character.toUpperCase(ch); //Step a
index = (int) ch - 65; //Step b
if(index >= 0 && index < 26) //Step c
letterC[index]++;
}

static void writeTotal(PrintWriter outfile, int lines,
int[] letters)
{
int i;

outfile.println("The number of lines = " + lines);

for(i = 0; i < 26; i++)
outfile.println((char)(i+65) + " count = " + letters[i]);
}
}

how to throws and handles the ArrayIndexOutOfBoundsException if the array index goes out of bounds when the program accesses the array letterCount

ASKER CERTIFIED SOLUTION

InteractiveMind

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georges_nassar

ASKER

i'm using textpad

i want to put a message ArrayIndexOutOfBoundsException when the array index goes out of bounds
can i put a message inside the method without using the method printStackTrace

i don't have stackTrace.txt

i found this:

import java.io.*;

public class PrintStackTraceExample1
{
public static void main (String[] args)
{
try
{
methodA();
}
catch(Exception e)
{
System.out.println(e.toString() + " caught in main");
e.printStackTrace();
}
}

static void methodA() throws Exception
{
methodB();
}
static void methodB() throws Exception
{
methodC();
}

static void methodC() throws Exception
{
throw new Exception("Exception generated in method C");
}
}

how can i do my program the same like it

InteractiveMind

I'm not sure if I understand... do you mean like this:

throw new ArrayIndexOutOfBoundsException( "The error message that you want to display here." );

?

georges_nassar

ASKER

yes

georges_nassar

ASKER

how to do it

InteractiveMind

..How to do what? :o\

What is it exactly that you want to achieve here?

btw, if you only want to count the number of characters in a file, and then output the result to another file, then it's as simple as this:

import java.io.*;

public class CharacterCount
{
private String inputFile = "F:\\text.txt";
private String outputFile = "F:\\textCh.out";

public CharacterCount() {}

public static void main( String [] args )
{
new CharacterCount().count();
}

public void count()
{
try
{
BufferedWriter out = new BufferedWriter( new FileWriter( outputFile ) );
out.write( "" + (new File( inputFile )).length() );
out.close();
} catch ( Exception e )
{
e.printStackTrace( System.out );
}
}
}