Middle three digits: Difference between revisions

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 =={{header|Picat}}==
+===Prolog-style===
-Two get_middle/1 functions:
-* get_middle_f1/1: {{trans|Prolog}}
+{{trans|Prolog}}
+<lang Picat>get_middle_f1(Str) = [X,Y,Z] =>
-* get_middle_f2/1: Using string length and list range
+  append(Pre,[X,Y,Z],Post,Str),
+  length(Pre) = length(Post).</lang>
+===List slice===
+<lang Picat>get_middle_f2(Str) = Str[Mid-1..Mid+1] =>
+  Mid = 1 + Str.len div 2.</lang>
+===Test===
 <lang Picat>go =>
   Success = [123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -12345],
@@ Line 4,449: / Line 4,456: @@
   if Len mod 2 = 0 then throw $not_odd_length(N)
   elseif Len < 3   then throw $number_too_small(N)
-  end.
+  end.</lang>
-% inspired by the Prolog solution
-get_middle_f1(Str) = [X,Y,Z] =>
-  append(Pre,[X,Y,Z],Post,Str),
-  length(Pre) = length(Post).
+{{out}}
-% Using slice
-get_middle_f2(Str) = Str[Mid-1..Mid+1] =>
-  Mid = 1 + Str.len div 2.</lang>
-Both tests outputs:
 <pre>[n = 123,middle = 123]
 [n = 12345,middle = 234]
@@ Line 4,478: / Line 4,476: @@
 [n = -2002,exception = not_odd_length(-2002)]
 [n = 0,exception = number_too_small(0)]</pre>
 =={{header|PicoLisp}}==