Update and rename check_valid_ip_address.py to is_ip_v4_address_valid.py

New test cases that the algorithm must detect:
* [ ] an octet much bigger than 255
* [ ] an octet is negative
* [ ] number of octets is less than 4
* [ ] number of octets is greater than 4
* [ ] an octet is a letter

Author: cclauss

maths/check_valid_ip_address.py

@@ -0,0 +1,50 @@
+"""
+Is IP v4 address valid?
+A valid IP address must be four octets in the form of A.B.C.D,
+where A,B,C and D are numbers from 0-254
+for example: 192.168.23.1, 172.254.254.254 are valid IP address
+             192.168.255.0, 255.192.3.121 are invalid IP address
+"""
+
+
+def is_ip_v4_address_valid(ip_v4_address: str) -> bool:
+    """
+    print "Valid IP address" If IP is valid.
+    or
+    print "Invalid IP address" If IP is invalid.
+
+    >>> is_ip_v4_address_valid("192.168.0.23")
+    True
+
+    >>> is_ip_v4_address_valid("192.255.15.8")
+    False
+
+    >>> is_ip_v4_address_valid("172.100.0.8")
+    True
+
+    >>> is_ip_v4_address_valid("254.255.0.255")
+    False
+
+    >>> is_ip_v4_address_valid("1.2.33333333.4")
+    False
+
+    >>> is_ip_v4_address_valid("1.2.-3.4")
+    False
+
+    >>> is_ip_v4_address_valid("1.2.3")
+    False
+
+    >>> is_ip_v4_address_valid("1.2.3.4.5")
+    False
+
+    >>> is_ip_v4_address_valid("1.2.A.4")
+    False
+    """
+    octets = [int(i) for i in ip_v4_address.split(".") if i.isdigit()]
+    return len(octets) == 4 and all(0 <= int(octet) <= 254 for octet in octets)
+
+
+if __name__ == "__main__":
+    ip = input().strip()
+    valid_or_invalid = "valid" if is_ip_v4_address_valid(ip) else "invalid"
+    print(f"{ip} is a {valid_or_invalid} IP v4 address.")