exam02 instructions

Instructions:

• This exam is 2hrs, in-class, on-paper.
• Please use any suggested abbreviations, to save writing. In addition, I recommend using short (but mnemonic) field-names (3 letters or so). E.g., str+ for string-append, str=? for string=?, def/c for define/contract, def-str/c for define-struct/c, mk-… for make-…, and nat? for natural?.
• Unless otherwise specified, you may write any exam-code in Java, or in Racket.
  You may even switch languages between problems; just be sure to use the correct field/struct names.
  For each java method, specify which class that method belongs in.
• If using Java, you may assume we are using records (so you have a standard/boilerplate constructor, toString, equals, and hashCode).
For parsing, you can use either java.util.Scanner methods next(), hasNext(String), nextDouble(),hasNextDouble(), or a Racket scanner with functions peek and pop!.

// Java: boolean hasNext( String s ) /* Is the next token equal to `s` (or, matches `s` as a regex)? Consumes no input. */ boolean hasNextDouble() /* Is the next token a numeral? Consumes no input. */ String next() /* Return the next token from the input stream, consuming it. */ String next( String s ) /* Return the next token from the input stream, consuming it; throw exception if the token doesn't match the regular expression `s`. */ boolean nextDouble() /* Return the next token from the input stream as a double, consuming it. */ ;; Racket: peek : scanner → String ; return the next token from the input stream, not consuming it. pop! : scanner → String ; return the next token from the input stream, consuming it.

Assume that the scanner correctly accounts for how punctuation separates tokens (for the exam you can pretend java.util.Scanner does this; for the project, we needed the UtilIan methods to do so).
• For any question, you may use functions defined in previous questions and assume they are correct, even if you didn't complete the previous question.