These are questions from system level programming course.

2. Write down the extended regular expression for following questions. E.g. Social security number in the format of 999-99-9999. Answer: [0-9]{3}-[0-9]{2}-[0-9]{4} 1) 1) Valid date format in the format of MMM-DD, YYYY. Note: the first character of the month is capitalized. (e.g. May-09,2008 Apr-19,2018 Jan-01,2000) 2) An account name which is 8 to 15 characters long, begins with a letter or underscore, ends with a digit, and composed by letters, numbers, underscores and hyphens. (e.g. my_Name1, cat_2, One-1) 3) A single-line comment starting with a # and continuing until the end of the line. Note: only whitespace is allowed between the start of the line and the comment. (e.g. #This program outputs the string hello world. ) 4) Integers in the range between 00 and 99. (e.g. 0, 00, 01, 15, 55, 59,99) 5) Phone number in any of the following format: 999-(999)9999, 999999-9999, 999.999-9999. (Note: all of these formats should be matched by a single regular expression) stp