Prefix and Suffix Functions

Both classes of functions are related

• prefix functions scan along an array. Each element of the result depends upon the preceding elements (in array element order). For example,

  PRODUCT_PREFIX((/1,2,3,4/)) = (/1,2,6,24/)
  PRODUCT_PREFIX((/1,4,7/), = ((/1, 24,  5040/),
                 (/2,5,8/), =  (/2,120, 40320/),
                 (/3,6,9/)) =  (/6,720,362880/))

• suffix functions do the same but scan backwards.

  PRODUCT_SUFFIX((/1,2,3,4/)) = (/24,24,12,4/)
  PRODUCT_SUFFIX((/1,4,7/), = ((/362880,60480,504/),
                 (/2,5,8/), =  (/362880,15120, 72/),
                 (/3,6,9/)) =  (/181440, 3024,  9/))