Rosetta Code:Village Pump/Suggest a programming task: Difference between revisions

Send an ICMP ping to some local resource, such as the current default gateway or even just 127.0.0.1 or ::1, and display information about the response or the absence of the response.

=== Generate a Regular Expression for a Range of Integers ===

Write a function that, given the integers 0 <= min < = max, returns a regular expression that will match the decimal representation of any integer in the range [min, max]. You may assume there are no thousand-separators, leading 0's, or other problematic characters in the string to be processed. You may also assume the caller of your function will prepend/append appropriate anchors (e.g., ^, $, or \b) depending on need, so don't include them. Don't use \d as an alias for [0-9] since \d can match weird unicode characters on some systems.

Example:

min = 1

max = 31

possible result = [1-9]|[1-2][0-9]|3[0-1]

possible result = [1-9]|[12][0-9]|3[01]

Example:

min = 91

max = 417

possible result = 9[1-9]|[1-3][0-9]{2}|4(0[0-9]|1[0-7])

possible result = 9[1-9]|[1-3][0-9][0-9]|4(0[0-9]|1[0-7])

Hint: Use a recursive, divide-and-conquer approach. You will have to handle cases where max contains more digits than min.

Bonus: support ranges containing negative integers.