2 Replies Latest reply on May 14, 2010 6:52 PM by jschellSomeoneStoleMyAlias

# Failing to code algorithm

Hi,

consider the following situation:

- I have an array of Class-objects

I need to check if the Class-objects inside the arrays are primitive-wrappers (Integer.class, Boolean.class, Character.class,...)
If they are, I want 2 Class[]-arrays (one with the wrapper, one with the primitive).

Still following?

Example:
``Class[] classes = new Class[] { String.class, Boolean.class, Double.class };``
I want to pass this to my function and retrieve a List<Class[]> object that contains the following Class[]-arrays
- String.class, Boolean.class, Double.class
- String.class, boolean.class, Double.class
- String.class, Boolean.class, double.class
- String.class, boolean.class, double.class

So when there's 2 primitive-wrappers, I receive a list of 4 Class[]-arrays, if there are 20 wrappers, I'd receive a list of 400 Class[]-arrays.

Is there a standard algorithm for this?
If not, some help is welcome.

B.
• ###### 1. Re: Failing to code algorithm
So when there's 2 primitive-wrappers, I receive a list of 4 Class[]-arrays, if there are 20 wrappers, I'd receive a list of 400 Class[]-arrays.
I can see little correction here. when you 2 primitive-wrappers, you should expect 2^2=4 class[]-arrays
for 3 primitive-wrappers, you should expect 2^3=8 class[]-arrays
for 4 primitive-wrappers, you should expect 2^4=16 class[]-arrays
for 5 primitive-wrappers, you should expect 2^5=32 class[]-arrays
Similarly for 20 primitive-wrappers, you should expect 2^20 class[]-arrays.

Also As per my knowledge I couldn't see any direct solution of it from java. One hint is, you need to maintain list/map of all primitives and their wrappers while working on it.
• ###### 2. Re: Failing to code algorithm
thierensb wrote:
Is there a standard algorithm for this?
No.
If not, some help is welcome.
What is the problem? It is solved with some if/else structures and nothing else is really needed.