tasks a-s

Task/Roman-numerals-Decode/Delphi/roman-numerals-decode.delphi

@@ -0,0 +1,44 @@
+program RomanNumeralsDecode;
+
+{$APPTYPE CONSOLE}
+
+function RomanToInteger(const aRoman: string): Integer;
+  function DecodeRomanDigit(aChar: Char): Integer;
+  begin
+    case aChar of
+      'M', 'm': Result := 1000;
+      'D', 'd': Result := 500;
+      'C', 'c': Result := 100;
+      'L', 'l': Result := 50;
+      'X', 'x': Result := 10;
+      'V', 'v': Result := 5;
+      'I', 'i': Result := 1
+    else
+      Result := 0;
+    end;
+  end;
+
+var
+  i: Integer;
+  lCurrVal: Integer;
+  lLastVal: Integer;
+begin
+  Result := 0;
+
+  lLastVal := 0;
+  for i := Length(aRoman) downto 1 do
+  begin
+    lCurrVal := DecodeRomanDigit(aRoman[i]);
+    if lCurrVal < lLastVal then
+      Result := Result - lCurrVal
+    else
+      Result := Result + lCurrVal;
+    lLastVal := lCurrVal;
+  end;
+end;
+
+begin
+  Writeln(RomanToInteger('MCMXC'));    // 1990
+  Writeln(RomanToInteger('MMVIII'));   // 2008
+  Writeln(RomanToInteger('MDCLXVI'));  // 1666
+end.