# Arrays

Arrays provide functionality to allocate a series of numbers to a parameter.

Arrays are supported and indexed with the notation such as #a[5]. More complex arrays are supported where the array is constructed from an expression:
#am_0[3*#i+ceil(#r[2])]
The expression between the square brackets must evaluate to an integer number, which can also be negative. The implementation of using arrays is such that they do not need to be allocated, however they need to be initialised.
Consider the following lines of code:
!!for #i = 10 to 20
#array_a[#i] = 3*#i-10
#array_b[-#i] = 0
!!next
It would be possible to use #array_a[10] or #array_a[17] or also #array_b[-12] in other expressions. But, trying to use for instance #array_a[5] or #array_b[0] results in an error message that an undefined variable is used.