[SOLVED] Csci 4230 – assignment 1

1. Write regular expressions for the following. The alphabet in question consists of a, b, and c.
(a) Strings that start with a followed by zero or more occurrences of b.
(b) Strings that start with a followed by zero or more occurrences of either b or c.
(c) Strings that start with a followed by one or more occurrences of b.
(d) Strings that have an even number of characters.
(e) Strings that have an odd number of characters.2. Write a regular expression for a string literal defined as follows:
• Starts with a “.
• Ends with a “.
• Between these two characters a string literal may contain any number of characters that are not
a ” or a . You can represent such a character with the symbol normal_char, which you do not
have to define separately.
• In addition a string literal can contain any of the following escape codes:
, ”, and \.
• Examples include “”, “Hello”, and “Hello, World!
”.3. Write a regular expression for an identifier defined as follows:
• Must start with a letter or a _.
• After the first character, there may be any number of digits, letters, or underscores.
• Use [0-9] to represent a single digit and [a-zA-Z] to represent a single letter.
• Examples include x, MyVar, my_var, and my_var3.4. Write a regular expression for a floating point number defined as follows:
• A sequence of digits followed by a . followed by a sequence of digits.
• The sequence before the . may be empty and can only start with 0 if it is the only digit in the
sequence.
• The sequence after the . must contain at least one digit.
• Examples include 0.5, 3.141592, 256.0, and .142857.