How do you validate that a string is a valid IPv4 address in C++?
I don't need to validate that the IP address is reachable or anything like that. I just want to validate that the string is in dotted-quad (xxx.xxx.xxx.xxx) IPv4 format, where xxx is between 0 and 255.
You probably want the inet_pton - which returns -1 on failure, and supports both the IPv4 and future IPv6 addresses. If you still need to write your own IP address system, remember that a standard 32-bit hex number is a valid IP address but not in dotted-decimal notation.
This function both verifies the address, and also allows you to use the same address in related socket calls.