Every character in a font is associated with a code or number. Codes are usually standard and conform to the ASCII or Unicode standard. For example, the code of capital A is 65, B's 66, lower-case a's is 97, b's 98 and so on. Special characters like !, &, $ have their own codes. However different computer platforms may use different mapping of characters. For example, Macs and PCs handle font encodings differently.