new files

Task/Search-a-list/Erlang/search-a-list.erl

@@ -0,0 +1,15 @@
+-module(index).
+-export([main/0]).
+
+main() ->
+    Haystack = ["Zig","Zag","Wally","Ronald","Bush","Krusty","Charlie","Bush","Bozo"],
+    Needles = ["Washington","Bush"],
+    lists:foreach(fun ?MODULE:print/1, [{N,pos(N, Haystack)} || N <- Needles]).
+
+pos(Needle, Haystack) -> pos(Needle, Haystack, 1).
+pos(_, [], _) -> undefined;
+pos(Needle, [Needle|_], Pos) -> Pos;
+pos(Needle, [_|Haystack], Pos) -> pos(Needle, Haystack, Pos+1).
+
+print({Needle, undefined}) -> io:format("~s is not in haystack.~n",[Needle]);
+print({Needle, Pos}) -> io:format("~s at position ~p.~n",[Needle,Pos]).