June 2018 Update

Task/Middle-three-digits/Aime/middle-three-digits.aime

@@ -4,18 +4,15 @@ m3(integer i)
     text s;
 
     s = itoa(i);
-    if (character(s, 0) == '-') {
+    if (s[0] == '-') {
         s = delete(s, 0);
     }
 
-    if (length(s) < 3) {
+    if (~s < 3) {
         v_integer(i);
         v_text(" has not enough digits\n");
-    } elif (length(s) & 1) {
-        o_winteger(9, i);
-        o_text(": ");
-        o_text(cut(s, length(s) - 3 >> 1, 3));
-        o_byte('\n');
+    } elif (~s & 1) {
+        o_form("/w9/: ~\n", i, cut(s, ~s - 3 >> 1, 3));
     } else {
         v_integer(i);
         v_text(" has an even number of digits\n");

Task/Middle-three-digits/Elena/middle-three-digits.elena

@@ -0,0 +1,29 @@
+import system'routines.
+import extensions.
+
+middleThreeDigits = (:n)<int>
+[
+    literal s := n absolute; literal.
+    int len := s length.
+    if(len<3)
+    [
+        InvalidArgumentException new:"n must have 3 digits or more"; raise
+    ];
+    if(len isEven)
+    [
+        InvalidArgumentException new:"n must have an odd number of digits"; raise
+    ].
+
+    int mid := len / 2.
+
+    ^ s Substring(mid-1,3).
+].
+
+program =
+[
+    (123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -12345, 1, 2, -1, -10, 2002, -2002, 0)
+    forEach(:n)
+    [
+        console printLine("middleThreeDigits(",n,"):",middleThreeDigits eval(n) | if(:e)(e message))
+    ]
+].

Task/Middle-three-digits/Factor/middle-three-digits.factor

@@ -0,0 +1,26 @@
+USING: combinators formatting io kernel math math.parser
+sequences ;
+IN: rosetta-code.middle-three-digits
+
+CONSTANT: test-values { 123 12345 1234567 987654321 10001 -10001
+    -123 -100 100 -12345 1 2 -1 -10 2002 -2002 0 }
+
+: middle-three ( str -- str' ) [ midpoint@ ] keep
+    [ [ 1 - ] [ 2 + ] bi ] dip subseq ;
+
+: too-short ( -- ) "Number must have at least three digits."
+    print ;
+
+: number-even ( -- ) "Number must have an odd number of digits."
+    print ;
+
+: process ( n -- )
+    abs number>string {
+        { [ dup length 3 < ] [ drop too-short ] }
+        { [ dup length even? ] [ drop number-even ] }
+        [ middle-three print ]
+    } cond ;
+
+: main ( -- ) test-values [ dup "%9d : " printf process ] each ;
+
+MAIN: main

Task/Middle-three-digits/Julia/middle-three-digits.julia

@@ -1,17 +1,16 @@
-function middle(i)
-    s = string(abs(i))
+function middle3(n::Integer)
+    s = dec(abs(n))
     l = length(s)
-    mid = round(Int,(l+1)/2)
-    l < 3 ?
-        "error: not enough digits"  :
-    iseven(l) ?
-        "error: number of digits is even"  :
-    s[mid-1:mid+1]
+    if iseven(l)
+        throw(ArgumentError("n must have an odd number of digits"))
+    elseif l < 3
+        throw(ArgumentError("n must have 3 digits or more"))
+    end
+    mid = (l + 1) ÷ 2
+    return s[mid-1:mid+1]
 end
 
-julia>
-
 for n = [123, 12345, 1234567, 987654321, 10001, -10001, -123,
          -100, 100, -12345, 1, 2, -1, -10, 2002, -2002, 0]
-    println (@sprintf("%10d : ", n), middle(n))
+    @printf("%10d -> %s\n", n, try middle3(n) catch e e.msg end)
 end

Task/Middle-three-digits/Kotlin/middle-three-digits.kotlin

@@ -1,14 +1,16 @@
 fun middleThree(x: Int): Int? {
     val s = Math.abs(x).toString()
-    when {
-        s.length < 3 -> return null // throw Exception("too short!")
-        s.length % 2 == 0 -> return null // throw Exception("even number of digits")
-        else -> return ((s.length / 2) - 1).let { s.substring(it, it + 3) }.toInt()
+    return when {
+        s.length < 3 -> null // throw Exception("too short!")
+        s.length % 2 == 0 -> null // throw Exception("even number of digits")
+        else -> ((s.length / 2) - 1).let { s.substring(it, it + 3) }.toInt()
     }
 }
 
-println(middleThree(12345)) // 234
-println(middleThree(1234)) // null
-println(middleThree(1234567)) // 345
-println(middleThree(123))// 123
-println(middleThree(123555)) //null
+fun main(args: Array<String>) {
+    println(middleThree(12345)) // 234
+    println(middleThree(1234)) // null
+    println(middleThree(1234567)) // 345
+    println(middleThree(123))// 123
+    println(middleThree(123555)) //null
+}

Task/Middle-three-digits/VBA/middle-three-digits.vba

@@ -0,0 +1,21 @@
+Option Explicit
+
+Sub Main_Middle_three_digits()
+Dim Numbers, i&
+    Numbers = Array(123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, _
+    100, -12345, 1, 2, -1, -10, 2002, -2002, 0)
+    For i = 0 To 16
+        Debug.Print Numbers(i) & " Return : " & Middle3digits(CStr(Numbers(i)))
+    Next
+End Sub
+
+Function Middle3digits(strNb As String) As String
+    If Left(strNb, 1) = "-" Then strNb = Right(strNb, Len(strNb) - 1)
+    If Len(strNb) < 3 Then
+        Middle3digits = "Error ! Number of digits must be >= 3"
+    ElseIf Len(strNb) Mod 2 = 0 Then
+        Middle3digits = "Error ! Number of digits must be odd"
+    Else
+        Middle3digits = Mid(strNb, 1 + (Len(strNb) - 3) / 2, 3)
+    End If
+End Function