Can you build an array with a for loop

[eluser]ppwalks[/eluser]
I am trying to build an array to insert into db, I have a count and want to build the array according to the count so used a for loop, except it is only showing the last result of the array so could someone help with this please.

Code:

$count = count($_POST['cat_id']);

for ($i=1; $i<=$count; $i++)
  {
  $product = array( $i => $prod);
  }

The ouput to screen is:

( [7] => 126 )

when it should start from 1 and increment to 7 as a for loop should, where am i going wrong