Array Problem

lad12

Anyone tell me how to reset an array

i set the array to 100..but the if the user enters only fills ten elements...how can i print these without getting an error like


Console: IO Exception in readInt();



Please

Imposter

What?
The middle line above makes no sense.
Also if you're getting an exception it doesn't neccesarily mean that you need to reset the array. What exactly are you trying to do? Possibly post some code and the exception you get.

lad12

Console: IO Exception in readInt();

is the exception i get....


i use a

Test.get();
while(!Console.EndOfFile())
{
Test.get();
}
Test.sort();
Test.print();


and i have set Test to 100 in

Tester test = new Tester(100)

where Tester is a class that sets test up as an array

when i want the program to finish by exiting the while loop i want it to then sort and print but i just get an error of

Console: IO Exception in readInt();

Imposter

Try this:

Test.get();
try{
while(!Console.EndOfFile())
{
Test.get();
}
}catch(IOException ioe){}
Test.sort();
Test.print();

If this is the same assignment as yesterday it was more or less done for you then!

OfflerCrocGod

Or dont cause that will print out ten numbers and cause 90 exceptions!!!. lad12 use a int n=0; and increase n++ everytime you get(); something from the user, then let .print(); take in that n and do a loop 0 to n printing out the nubers the person inputed and then ingnoring the empty array spaces.

lad12

Yeah ive tried that

like in class Tester i declare
private int n = 0;

then in my get method i place n++, and ive reset the 2 for loops to
for(int i = 0; i < n; i++)
test.print(i);

but i still get Console: IO Exception in readInt();

and Excetion in thread "main" java.lang.nullPointerException

Imposter

Originally posted by OfflerCrocGod
Or dont cause that will print out ten numbers and cause 90 exceptions!!!.

True.

But the next question would be fun then!

henbane

Originally posted by lad12
Test.get();
while(!Console.EndOfFile())
{
Test.get();
}
Test.sort();
Test.print();

This is almost certainly a Joe Morris course. Read the next set of notes. If I remember correctly, he advised to increment a counter every time you add to the array and then use that to make sure you don't throw exceptions cos you won't read any index above the size of the counter.

You really should just read his notes - they're rather good.

lad12

eh hem..yes

lad12

Thanks for the advise henbane....got it working perfectly..cheers

OfflerCrocGod

Use the n++ then print out the value for n, after you have inputed 10 numbers. It should say 10, if not your problem is there, is if does then your prob is elsewere. Actually print n every time you get a number in just to make sure you are getting the n part right. wait....what does sort() do?.

<edit>Whatever:rolleyes:.

Karoma

why not let the user specify how many elements that they want to put in?


quick'n'durtay:

import java.util.*;
import java.io.*;

public class Test
{

  

  public static void main(String[] args)
  {

    int arrLength = 0; // the length of the array.set by user below..
    int i; //counter
    
    // reading in
    BufferedReader in = new BufferedReader(new InputStreamReader(System.in));



    try 
    { //get user to set array length (from keyboard)

        
        String str = "";
 	i = 0;

        while ( i != 1) 
        {
            System.out.print("> How many elements in the array? ");
            str = in.readLine(); //read
            System.out.println("you input: " +str); //for test..

            arrLength = Integer.parseInt( str); //change to int

	    i++; //get out of loop
            
        }


    } 
    catch (IOException e) 
    {
       //err 
    }





    //create the array. size = what the user said.
    int[] testArr = new int[ arrLength ];


    try 
    {

	int inpt;
	i = 0; //reset our counter

        while ( i != arrLength ) 
        { // get input from user (to put in the array)

            System.out.print("Input element in the array > "); //prompt
            inpt = Integer.parseInt( in.readLine() ); //read in
            System.out.println("you input: " + inpt); // test
 
            testArr[i] = inpt; //put into array
	    i++; //loop counter inc.
        }
   }
   catch(IOException ioe){ }


    
    //test: print elements in array
    System.out.println( "The array length is: " + testArr.length); 
    for ( int n =0; n < testArr.length; n++)
    {
      System.out.println("element at " + n + " equals" + testArr[n] );
    }


  }


}

Silent Bob

The real problem is that you're using an array where you really want to be using a vector.

Vectors are designed for situations where you don't know at compile time how many items need to be stored in them.

Karoma

*grumbles*
these discussions are coming up a lot lately... "change array to vector" "vector to arraylist" ...
He asked for help with an array so we gave him help with an array; but SB is correct- you'd be better off using either a vector or arraylist...