Just another update

Task/Middle-three-digits/ALGOL-68/middle-three-digits.alg

@@ -0,0 +1,92 @@
+# we define a UNION MODE so that our middle 3 digits PROC can #
+# return either an integer on success or a error message if   #
+# the middle 3 digits couldn't be extracted                   #
+
+MODE EINT = UNION( INT # success value #, STRING # error message # );
+
+
+# PROC to return the middle 3 digits of an integer.           #
+# if this is not possible, an error message is returned       #
+# instead                                                     #
+
+PROC middle 3 digits = ( INT number ) EINT:
+BEGIN
+
+    # convert the absolute value of the number to a string with the  #
+    # minumum possible number characters                             #
+    STRING digits     = whole( ABS number, 0 );
+    INT    len        = UPB digits;
+
+
+    IF   len < 3
+    THEN
+        # number has less than 3 digits #
+        # return an error message       #
+
+        "number must have at least three digits"
+
+    ELIF ( len MOD 2 ) = 0
+    THEN
+        # the number has an even number of digits #
+        # return an error message                 #
+
+        "number must have an odd number of digits"
+
+    ELSE
+        # the number is suitable for extraction of the middle 3 digits #
+
+        INT first digit pos = 1 + ( ( len - 3 ) OVER 2 );
+
+        # the result is the integer value of the three digits          #
+
+        ( ( ( ABS digits[ first digit pos     ] - ABS "0" ) * 100 )
+        + ( ( ABS digits[ first digit pos + 1 ] - ABS "0" ) *  10 )
+        + ( ( ABS digits[ first digit pos + 2 ] - ABS "0" )       )
+        )
+
+    FI
+
+END; # middle 3 digits #
+
+
+
+main: (
+
+    # test the middle 3 digits PROC #
+
+    []INT test values = (    123,  12345, 1234567, 987654321
+                        ,  10001, -10001,    -123,      -100
+                        ,    100, -12345
+                          # the following values should fail #
+                        , 1, 2, -1, -10, 2002, -2002, 0
+                        );
+
+    FOR test number FROM LWB test values TO UPB test values
+    DO
+
+        CASE middle 3 digits( test values[ test number ] )
+        IN
+        ( INT     success value ):    # got the middle 3 digits #
+
+            printf( ( $ 11z-d, " : ", 3d $
+                    , test values[ test number ]
+                    , success value
+                    )
+                  )
+            ,
+
+        ( STRING  error message  ):    # got an error message   #
+
+            printf( ( $ 11z-d, " : ", n( UPB error message )a $
+                    , test values[ test number ]
+                    , error message
+                    )
+                  )
+
+        ESAC;
+
+        print( ( newline ) )
+
+    OD
+
+)

Task/Middle-three-digits/C++/middle-three-digits.cpp

@@ -1,84 +1,27 @@
 #include <iostream>
-#include <sstream>
-#include <string>
 
-// @author Martin Ettl
-// @date   2013-02-04
-
-/**
- * Convert variables of type T to std::string
- *
- *
- * @param d --> digit of type T
- *
- * @return <-- the corresponding string value
- */
-template <typename T> const std::string toString(const T &d)
+std::string middleThreeDigits(int n)
 {
-    std::ostringstream result;
-    result << d;
-    return result.str();
-}
+    auto number = std::to_string(std::abs(n));
+    auto length = number.size();
 
-/**
- * Determine the middle n digits of the integer. If it is not possible to determine the
- * the middle n digits, an empty string is provided.
- *
- * @param iDigit --> The digit to test
- * @param n      --> The number of digits inbetween
- *
- * @return <-- the middle three digits
- */
-std::string strMiddleNDigits(int iDigit, const int &n)
-{
-    // is negative: --> convert to a positive number
-    if(iDigit<0)
-    {
-        iDigit*=-1;
+    if (length < 3) {
+        return "less than three digits";
+    } else if (length % 2 == 0) {
+        return "even number of digits";
+    } else {
+        return number.substr(length / 2 - 1, 3);
     }
-    // convert to string
-    std::string strNumber (toString(iDigit));
-    size_t len(strNumber.length());
-    if( (len < n) || (len % 2 == 0) )
-    {
-        return "";
-    }
-    size_t mid(len/2);
-    return strNumber.substr(mid-n/2, n);
-}
-
-/**
- * Determine the middle three digits of the integer. If it is not possible to determine the
- * the middle three digits, an empty string is provided.
- *
- * @param iDigit --> The digit to test
- *
- * @return <-- the middle three digits
- */
-std::string strMiddleThreeDigits(int iDigit)
-{
-    return strMiddleNDigits(iDigit,3);
 }
 
 int main()
 {
-    const int iPassing[] = {123, 12345, 1234567, 987654321, 10001, -10001,
-                            -123, -100, 100, -12345
-                           };
-    for(unsigned int ui = 0; ui < 10; ++ui)
-    {
-        std::cout << "strMiddleThreeDigits("<< iPassing[ui] <<"): "
-                  << strMiddleThreeDigits(iPassing[ui])<< "\n";
-    }
+    auto values {123, 12345, 1234567, 987654321, 10001,
+                 -10001, -123, -100, 100, -12345,
+                 1, 2, -1, -10, 2002, -2002, 0};
 
-    const int iFailing[] = {1, 2, -1, -10, 2002, -2002, 0};
-    for(unsigned int ui = 0; ui < 7; ++ui)
-    {
-        std::string strResult = strMiddleThreeDigits(iFailing[ui]);
-        std::cout << "strMiddleThreeDigits("<< iFailing[ui] <<"): "
-                  << (strResult.empty()?"Need odd and >= 3 digits":strResult)
-                  << "\n";
+    for (auto&& v : values) {
+        std::cout << "middleThreeDigits(" << v << "): " <<
+                     middleThreeDigits(v) << "\n";
     }
-
-    return 0;
 }

Task/Middle-three-digits/D/middle-three-digits-1.d

@@ -1,7 +1,7 @@
-import std.stdio, std.traits, std.conv, std.range;
+import std.stdio, std.traits, std.conv;
 
-string middleThreeDigits(T)(in T n) if (isIntegral!T) {
-    auto s = n < 0 ? n.text().dropOne : n.text();
+string middleThreeDigits(T)(in T n) pure nothrow if (isIntegral!T) {
+    auto s = n < 0 ? n.text[1 .. $] : n.text;
     auto len = s.length;
     if (len < 3 || len % 2 == 0)
         return "Need odd and >= 3 digits";
@@ -12,10 +12,10 @@ string middleThreeDigits(T)(in T n) if (isIntegral!T) {
 void main() {
     immutable passing = [123, 12345, 1234567, 987654321, 10001, -10001,
             -123, -100, 100, -12345, long.min, long.max];
-    foreach (n; passing)
+    foreach (immutable n; passing)
         writefln("middleThreeDigits(%s): %s", n, middleThreeDigits(n));
 
-    immutable failing = [1, 2, -1, -10, 2002, -2002, 0, int.min, int.max];
-    foreach (n; failing)
+    immutable failing = [1, 2, -1, -10, 2002, -2002, 0,int.min,int.max];
+    foreach (immutable n; failing)
         writefln("middleThreeDigits(%s): %s", n, middleThreeDigits(n));
 }

Task/Middle-three-digits/Prolog/middle-three-digits-1.pro

@@ -0,0 +1,14 @@
+middle_3_digits(Number, [D1,D2,D3]) :-
+    verify_middle_3_able(Number, Digits),
+    append(FrontDigits, [D1,D2,D3| BackDigits], Digits),
+    same_length(FrontDigits, BackDigits).
+
+verify_middle_3_able(Number, Digits) :-
+    must_be(number, Number),
+    AbsNumber is abs(Number),
+    number_chars(AbsNumber, Digits),
+    length(Digits, NumDigits),
+    ( 3 > NumDigits         ->  domain_error('at least 3 digits',    Number)
+    ; 0 is NumDigits mod 2  ->  domain_error('odd number of digits', Number)
+    ; true
+    ).

Task/Middle-three-digits/Prolog/middle-three-digits-2.pro

@@ -0,0 +1,6 @@
+test_correct :-
+    TestCases = [123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -12345],
+    foreach( ( member(TestCase, TestCases),
+               middle_3_digits(TestCase, Result) ),
+            format('Middle 3 digits of ~w ~30|: ~w~n', [TestCase, Result])
+          ).

Task/Middle-three-digits/Ruby/middle-three-digits-1.rb

@@ -0,0 +1,14 @@
+def middle_three_digits(num)
+  # minus sign doesn't factor into digit count,
+  # and calling #abs acts as a duck-type assertion
+  num = num.abs
+
+  # convert to string and find length
+  length = (str = num.to_s).length
+
+  # check validity
+  raise ArgumentError, "Number must have at least three digits" if length < 3
+  raise ArgumentError, "Number must have an odd number of digits" if length.even?
+
+  return str[length/2 - 1, 3].to_i
+end

Task/Middle-three-digits/Ruby/middle-three-digits-2.rb

@@ -0,0 +1,14 @@
+samples = [
+  123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -12345,
+  1, 2, -1, -10, 2002, -2002, 0
+]
+
+left_column_width = samples.map { |n| n.to_s.length }.max
+samples.each do |n|
+  print "%#{left_column_width}d: " % n
+  begin
+    puts "%03d" % middle_three_digits(n)
+  rescue ArgumentError => e
+    puts e
+  end
+end

Task/Middle-three-digits/Ruby/middle-three-digits.rb

@@ -1,30 +0,0 @@
-def middle_three_digits(n)
-  # minus sign doesn't factor into digit count,
-  # and calling #abs acts as a duck-type assertion
-  n = n.abs
-
-  # convert to string and find length
-  l = (s = n.to_s).length
-
-  # check validity
-  raise ArgumentError, "Number must have at least three digits" if l < 3
-  raise ArgumentError, "Number must have an odd number of digits" if l.even?
-
-  return s[l/2-1,3].to_i
-end
-
-samples = [
-  123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -12345,
-  1, 2, -1, -10, 2002, -2002, 0
-]
-
-width = samples.map { |n| n.to_s.length }.max
-
-samples.each do |n|
-  print "%#{width}d: " % n
-  begin
-    puts "%03d" % middle_three_digits(n)
-  rescue ArgumentError => e
-    puts e
-  end
-end

Task/Middle-three-digits/SQL/middle-three-digits.sql

@@ -0,0 +1,12 @@
+;WITH DATA
+     AS (SELECT CAST(ABS(NUMBER) AS NVARCHAR(MAX))      charNum,
+                NUMBER,
+                LEN(CAST(ABS(NUMBER) AS NVARCHAR(MAX))) LcharNum
+         FROM   TABLE1)
+SELECT CASE
+         WHEN ( LCHARNUM >= 3
+                AND LCHARNUM % 2 = 1 ) THEN SUBSTRING(CHARNUM, LCHARNUM / 2, 3)
+         ELSE 'Error!'
+       END    Output,
+       NUMBER Input
+FROM   DATA