How to convert string to IP address and vice versa

how can I convert a string ipAddress (struct in_addr) and vice versa? and how do I turn in unsigned long ipAddress? thanks

Solution 1:

Use inet_ntop() and inet_pton() if you need it other way around. Do not use inet_ntoa(), inet_aton() and similar as they are deprecated and don't support ipv6.

Here is a nice guide with quite a few examples.

// IPv4 demo of inet_ntop() and inet_pton()

struct sockaddr_in sa;
char str[INET_ADDRSTRLEN];

// store this IP address in sa:
inet_pton(AF_INET, "192.0.2.33", &(sa.sin_addr));

// now get it back and print it
inet_ntop(AF_INET, &(sa.sin_addr), str, INET_ADDRSTRLEN);

printf("%s\n", str); // prints "192.0.2.33"

Solution 2:

I'm not sure if I understood the question properly.

Anyway, are you looking for this:

std::string ip ="192.168.1.54";
std::stringstream s(ip);
int a,b,c,d; //to store the 4 ints
char ch; //to temporarily store the '.'
s >> a >> ch >> b >> ch >> c >> ch >> d;
std::cout << a << "  " << b << "  " << c << "  "<< d;

Output:

192  168  1  54

Solution 3:

I was able to convert string to DWORD and back with this code:

char strAddr[] = "127.0.0.1"
DWORD ip = inet_addr(strAddr); // ip contains 16777343 [0x0100007f in hex]

struct in_addr paddr;
paddr.S_un.S_addr = ip;

char *strAdd2 = inet_ntoa(paddr); // strAdd2 contains the same string as strAdd

I am working in a maintenance project of old MFC code, so converting deprecated functions calls is not applicable.

Solution 4:

inet_ntoa() converts a in_addr to string:

The inet_ntoa function converts an (Ipv4) Internet network address into an ASCII string in Internet standard dotted-decimal format.

inet_addr() does the reverse job

The inet_addr function converts a string containing an IPv4 dotted-decimal address into a proper address for the IN_ADDR structure

PS this the first result googling "in_addr to string"!