Thread: Interger.parseInt Question

Hi,

I copied this code from a book, any while it will compile, I get an exception error when I try to run it. Any idea what the issue is?

class Power
{
public static void main ( String[] args )
{
int num = Integer.parseInt( args[0] ) ;
int square = (int) Math.pow( num, 2 ) ;
int cube = (int) Math.pow( num, 3 ) ;
int sqrt = (int) Math.sqrt( num ) ;
System.out.println( num + "squared is " + square ) ;
System.out.println( num + " cubed is " + cube ) ;
System.out.println( "Square root of " +num+" is " + sqrt ) ;
}
}

java.lang.ArrayIndexOutOfBoundsException:
0
at Power.main(power.java:5)

Thanks Norm,

I appreciate the response, but could you explain that in laymans terms? That would really help. Sorry, but I'm just starting out with Java.

Hi,

When an application is launched, the runtime system passes the command-line arguments to the application's main method via an array of Strings. You need to pass arguments while you run this code as on this line no 5 : int num = Integer.parseInt( args[0] ) ; you are fetching arguments from the command line.
so when you run the code using the command : java Power 2
you will get the output as below:
2squared is 4
2 cubed is 8
Square root of 2 is 1

can you please show me the exact code you used to correct it? That would really help me understand what I need to do. Thanks in advance.

Thanks for the reply Norm, Where exactly do I insert the line Java Power 2?

I'm using Bluej

Ok, that makes sense, I'll do that. Thanks for all your help Norm. I'm sure I'll be posting many, many more times in this forum, hehe.