Homework 2 Solution

Question 1:

{SLASH}{STAR}[^(*/)]*{STAR}{SLASH}

• Doesn't allow parentheses, stars, or slashes in the comment body: (good comment example) /* (*)(/) */

{SLASH}{STAR}(.)*{STAR}{SLASH}

• Allows */ in the comment body: (bad comment example) /* a */ */
• Doesn't allow a newline in the comment body: (good comment example)
  /* this is a
  multi-line comment */

{SLASH}{STAR}([^*]*{STAR}+[^*/])*{STAR}+{SLASH}

• Doesn't allow a non-empty comment body without a star: (good comment example) /* a */

{SLASH}{STAR}([^*]|[^/])+{STAR}{SLASH}

• Allows */ in the comment body: (bad comment example) /* */ */
• Doesn't allow a comment with an empty body: (good comment example) /**/

{SLASH}{STAR}[^*]*{STAR}+{SLASH}+

• Allows multiple / after the end of the comment: (bad comment example) /* *////
• Doesn't allow non-star to appear after a star in the comment body: (good comment example) /* *a */

Question 2:

{SLASH}{STAR}([^*]|({STAR}+[^*/]))*{STAR}+{SLASH}