isIPv4Address

IPv4 address is a string with the following structure: a.b.c.d, where a, b, c and dare integers in range [0, 255]. For example, 0.0.0.0, 255.255.255.255 or 252.0.128.32 are correct IPv4 addresses, and 0.0.0.256, -1.1.1.1, 0.0.0.0.0 are incorrect.

An IP address is a numerical label assigned to each device (e.g., computer, printer) participating in a computer network that uses the Internet Protocol for communication. There are two versions of the Internet protocol, and thus two versions of addresses. One of them is the IPv4 address.

Given a string, find out if it satisfies the IPv4 address naming rules.

Example

• For inputString = "172.16.254.1", the output should be
  isIPv4Address(inputString) = true;

• For inputString = "172.316.254.1", the output should be
  isIPv4Address(inputString) = false.

  316 is not in range [0, 255].

• For inputString = ".254.255.0", the output should be
  isIPv4Address(inputString) = false.

  There is no first number.

Input/Output

• [execution time limit] 0.5 seconds 

• [input] string inputString

  A string consisting of digits, full stops and lowercase English letters.

  Guaranteed constraints:
  1 ≤ inputString.length ≤ 30.

• [output] boolean

  • true if inputString satisfies the IPv4 address naming rules, false otherwise.