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Middle three digits: Difference between revisions
added ocaml
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middleThreeDigits(-2002) returned: Need odd and >= 3 digits
middleThreeDigits(0) returned: Need odd and >= 3 digits</pre>
=={{header|OCaml}}==
<lang ocaml>let even x = (x land 1) <> 1
let middle_three_digits x =
let s = string_of_int (abs x) in
let n = String.length s in
if n < 3 then failwith "need >= 3 digits" else
if even n then failwith "need odd number of digits" else
String.sub s (n / 2 - 1) 3
let passing = [123; 12345; 1234567; 987654321; 10001; -10001; -123; -100; 100; -12345]
let failing = [1; 2; -1; -10; 2002; -2002; 0]
let print x =
let res =
try (middle_three_digits x)
with Failure e -> "failure: " ^ e
in
Printf.printf "%d: %s\n" x res
let () =
print_endline "Should pass:";
List.iter print passing;
print_endline "Should fail:";
List.iter print failing;
;;</lang>
{{out}}
<pre>
Should pass:
123: 123
12345: 234
1234567: 345
987654321: 654
10001: 000
-10001: 000
-123: 123
-100: 100
100: 100
-12345: 234
Should fail:
1: failure: need >= 3 digits
2: failure: need >= 3 digits
-1: failure: need >= 3 digits
-10: failure: need >= 3 digits
2002: failure: need odd number of digits
-2002: failure: need odd number of digits
0: failure: need >= 3 digits
</pre>
=={{header|Python}}==
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