CS536 Homework 1 Solution

Question 1:

Question 2: (one possible solution)

[letter]([letter] | [digit] | [hyphen]([letter] | [digit]))*#[digit]+

Question 3:

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

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

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

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

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

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

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

• Allows */ in the comment body: /* */ */
• Doesn't allow a comment with an empty body: /**/

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

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

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

Question 4:

{SLASH}{SLASH}([^\n]*)\n

{SLASH}{SLASH}(.)*\n