Examples:

```Input  : 127.0.0.1
Output : 0x7f000001

Input  : 172.31.0.2
Output : 0xac1f0002

```

Explanation
using the Library function to convert the IP address to convert into the hexadecimal value we use ” arpa/inet.h “ header file. The inet_addr() function shall convert the string in the standard IPv4 dotted decimal notation, to an integer value suitable for use as an Internet address.

## C++

 `// C++ program for IP to ` `// hexadecimal conversion ` `#include ` `#include ` `#include ` `using` `namespace` `std; ` ` `  `// function for reverse hexadecimal number ` `void` `reverse(``char``* str) ` `{ ` `    ``// l for swap with index 2 ` `    ``int` `l = 2; ` `    ``int` `r = ``strlen``(str) - 2; ` ` `  `    ``// swap with in two-2 pair ` `    ``while` `(l < r) { ` `        ``swap(str[l++], str[r++]); ` `        ``swap(str[l++], str[r]); ` `        ``r = r - 3; ` `    ``} ` `} ` ` `  `// function to conversion and print ` `// the hexadecimal value ` `void` `ipToHexa(``int` `addr) ` `{ ` `    ``char` `str[15]; ` ` `  `    ``// convert integer to string for reverse ` `    ``sprintf``(str, ``"0x%08x"``, addr); ` ` `  `    ``// reverse for get actual hexadecimal ` `    ``// number without reverse it will ` `    ``// print 0x0100007f for 127.0.0.1 ` `    ``reverse(str); ` ` `  `    ``// print string ` `    ``cout << str << ``"\n"``; ` `} ` ` `  `// Driver code ` `int` `main() ` `{ ` `    ``// The inet_addr() function  convert  string ` `    ``// in to standard IPv4 dotted decimal notation ` `    ``int` `addr = inet_addr(``"127.0.0.1"``); ` ` `  `    ``ipToHexa(addr); ` ` `  `    ``return` `0; ` `} `

Outpur:-

```0x7f000001
```

My Personal Notes arrow_drop_up

Check out this Author's contributed articles.

If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.

Article Tags :

Be the First to upvote.

Please write to us at contribute@geeksforgeeks.org to report any issue with the above content.