These are questions from system level programming course.

Part II: Regular Expression 1. Chose match(es) for each given basic/extended regular expression (maybe multiple correct matches) and describe the pattern of matched string for 3), 4), 6), 11). e.g. 'ab+a' (extended regex) a) ababa b) aba cabba d)aabbaa ejaa Answer: b,c; Pattern : The matched string should begin and end with 'a' and 'b'occurs at least once between leading and ending 'a') Note: 1 to 5 are basic regexes; (b) aaba (c) aabab (d) aabbaa (e)aa (b) a?[bc] (c)a[bc (d) a? (C) abcbc 1) aab)*a' (a)ababa 2) a?[bc]*' (a) abc 3) ?[nd] * (a) wind 4) '[a-z]+[0-9] (a) a++ (b) window (c) end (d) good (e)will (b) aa++ (c) 6+ (d) a+6 (e) aa+1 Note: 5 to 12 are extended regexes. 5) faa|b)*a' (a)ababa (b) aaba (C) aabab (d) aabbaa (e)aa 6) [a-z](\-[a-z0-9]]+ (a)x+9 (b)x+y (c) 1 (d) y (e) x++y 7) fa (bc)*z (a)azbc (b) az (c) azbcbc (d) acc (e)acz 8) 'a.*[0-9]' (a)a[1 (b) a*2 (c) ab 2 (d) abc (e)aaa 9) '[a-t]+[\.\ ?!+]' (a)bash! (b) c (c) Java? (d) python! (e)c++ 10) [a-z]+[\,\?!]\s*[A-Z]' (hint: s matches any whitespace characters) (a)o. year (b)x?y (c) U.S. (d)Hello!HELLO (e)index?a 11) '(very\s)?(cool\s]+(good|bad) weather' (a very weather (b) very cool weather (C) good weather (d) very cool good weather (e)cool bad weather (d) -2.2 (e) 1.2 12) :-?([0-9]||[1-9][0-9]))' (a)123 (b) -123 (c)-0 13) '-?[0-9]*\.?[0-9]* (a)123 (b) -123 (0)-0 (d) -2.2 (e) 1.2