I have a project that I'm not making good headway on. The end product has to be written in C, but I want to make a perl prototype first.

Here's the deal: I need to write a function that gets two arguments:

• A set, sort of like {A, B, C}
• an integer, that specifies the size of the tuples to create.

This function will return a reference to a 2-d array. Each row in the array will be a tuple. For example,

my @set = qw(A B C);
my $output = mk_tuples(@set, 2);
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And $output would be a ref to a 2-d array that looks like this (each row is an array):

A A

A B

A C

B A

B B

B C

C A

C B

C C
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The number of tuples to be created is equal to the number of elements in the set raised to the power of the size of the tuples. In this case, that turns out to be 3**2, or 9.

The stumbling block for me is how to create the tuples. I can hear a voice in my head that says recursion might be useful, but I'm just not seeing it right now. Any help would be appreciated.

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