In COBOL, a string of not more than30characters, chosen from the following:the letters A through Z, the digits0through9, and the hyphen(-.The hyphen may not appear as either the first or last character.

• 在COBOL语言中，一种不超过30个字符的字符串，其字符从字母A到Z和数字0到9及连字符－中选取，但连字符不能出现在字首或字尾。