current community

your communities

more stack exchange communities

Stack Exchange
tour help
careers 2.0
Take the 2-minute tour ×
Stack Overflow is a question and answer site for professional and enthusiast programmers. It's 100% free, no registration required.
up vote -1 down vote favorite

I have a doubt. I am developing the following code which will be a multplication table for a number that you manually introduce. What I cannot get is to print the table. I don't know what is going on because as far as I know, all the code is right written.

public class Tabla 
{

public static void main (String[] args) 
{        
    int n=4;       

    Tabla table = new Tabla ();
    int dato [];
    dato=table.producto(n);        

    for (int j=1;j<=10;j++)
    {System.out.println(dato[j]);}

}



public int [] producto(int num) 
{ 
    int a[]={'0'};

    for (int i=1;i<=10;i++)
    {a[i]=num*i;}

    return a;


}    

}

Any ideas??

Thanks in advance!

**I changed the code to:

public class Tabla 
{

    public static void main (String[] args) 
    {        
        int n=4;       
        int j;

        Tabla table = new Tabla ();
        int dato[]=new int [10];
        dato=table.producto(n);        

        for (j=0;j<10;j++)
        {System.out.println(dato[j]);
        }

    }



    public int [] producto(int num) 
    { 
        // make a 10-element array
        int a[] = new int[10];

       // fill up the array with products
        for (int i = 0; i < 10; i++)
        {a[i] = num * (i+1); }

        return a;            

    }       
}

Works like a charm! Now I am wondering why the compiler threw the "ArrayIndexOutOfBoundsException" when I had the for cycle as for (int i = 1; i <=10; i++)

Thanks for the help! :D

share|improve this question

closed as too broad by Matt Ball, jahroy, Eran, Sean Owen, TGMCians Mar 2 at 15:14

There are either too many possible answers, or good answers would be too long for this format. Please add details to narrow the answer set or to isolate an issue that can be answered in a few paragraphs.If this question can be reworded to fit the rules in the help center, please edit the question.
1  
What happens when you run this code? –  Louis Wasserman Mar 27 '13 at 23:24
    
The following appears: run: Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 1 at tabla.Tabla.producto(Tabla.java:31) at tabla.Tabla.main(Tabla.java:17) Java Result: 1 GENERACIÓN CORRECTA (total time: 0 seconds) –  Mike Pérez Mar 27 '13 at 23:27
    
@MikePérez I fixed my code, so it should no longer throw any out-of-range exceptions. –  feralin Mar 27 '13 at 23:50

2 Answers 2

up vote 5 down vote accepted

Building off of Wasserman's answer, what you should have written is as follows:

public int[] producto(int num) 
{
    // make a 10-element array
    int a[] = new int[10];

    // fill up the array with products
    for (int i = 0; i < 10; i++)
        a[i] = num * (i + 1);

    return a;
}

You created a single-element array, whereas you wanted a 10-element array to fill up.

share|improve this answer
    
This will still throw an ArrayIndexOutOfBoundsException. –  Louis Wasserman Mar 27 '13 at 23:36
1  
loop from 0 to < 10 –  Kailua Bum Mar 27 '13 at 23:37
    
@LouisWasserman Oh, sorry! My mistake! I'll fix it now. –  feralin Mar 27 '13 at 23:38
    
@KailuaBum yup. –  feralin Mar 27 '13 at 23:38
    
Thanks buddies! All working well! :D –  Mike Pérez Mar 27 '13 at 23:47
up vote 3 down vote

Two problems:

int a[]={'0'};

This line creates an array a with only one element -- not the 11 you're trying to fill -- and moreover, that one element is the ASCII code for the character 0, which is almost certainly not what you want.

share|improve this answer
    
Thanks, I changed the integer variables but nothing happens yet... Any idea why? –  Mike Pérez Mar 27 '13 at 23:34
    
@MikePérez take a look at my answer. Does that work? –  feralin Mar 27 '13 at 23:36
    
No, I have no idea why, because I have no idea what you've changed. Post your updated code. –  Louis Wasserman Mar 27 '13 at 23:36
    
@LouisWasserman isn't Mike Pérez making a 10-element array, not 11 elements? –  feralin Mar 27 '13 at 23:37
    
@feralin: Reread the for loop. –  Louis Wasserman Mar 27 '13 at 23:37

Not the answer you're looking for? Browse other questions tagged or ask your own question.