Let me clear up a common misconception. When most people say writing in code, what they really mean is writing using a cipher. A code is when a symbol, word, or phrase is used to stand for a different word, phrase, or sentence. A cipher is were each letter in a word is represented with a different letter or symbol.
The dash is a punctuation mark that is similar to a hyphen or minus sign, but differs from both of these symbols primarily in length and function.
1 The figure dash is a special typographical character most often used in phone numbers. Since it's normally unavailable in word processing, you can simply use a hyphen. (Example: 408â555â6792, or use 408-555-6792.)  An en dash (â) is most commonly used to indicate a range of numbers.