1. Here are regular expressions used to define floating point (flopo) numbers:
digs = [0-9]+ flopo = digs (. digs)? (E (+|-)? digs)?
where (...)? stands for "option": zero or one of the regular expression inside the parentheses. For the following strings, determine whether they are valid flopo-s:
.5 123 0.5 123E4 123.45E+67
2. Here is our grammar for arithmetic expressions:
expr = term ( "+"|"-" term )* term = factor ( "*"|"/" factor )* factor = number | "(" expr ")" number = [0-9]+For the following strings, determine whether they are valid expr-s. If they are, show their derivation, either as a complete sequence of derivation steps, or as a parse tree.
1 + -3 2 * 3 - 4 3 * 4 / 5 (3 * 4) / 5 1/2/3/4 1-2/3-4
3. Go through your quizzes and homework. Study what you did right or wrong, and fix your mistakes. Be ready to ask questions about the topics to be studied.