Search Engine Algorithms

Smalltalk

Smalltalk indexes start at 1.

| haystack |
haystack := 
   'Zig,Zag,Wally,Ronald,Bush,Krusty,Charlie,Bush,Bozo' subStrings: $,.

{ 'Washington' . 'Bush'  } do: [:i|

  |t l|
  t := (haystack indexOf: i).

  (t = 0) ifTrue: [ ('%1 is not in the haystack' % { i }) displayNl ]

          ifFalse: [ ('%1 is at index %2' % { i . t }) displayNl.

                     l := ( (haystack size) - (haystack reverse indexOf: i) + 1 ).

                     ( t = l ) ifFalse: [ 

                       ('last occurence of %1 is at index %2' % 
                             { i . l }) displayNl ]

                   ]
].