Print Reverse of a string using Recursion

Print reverse of a  string using recursion:

# include <stdio.h>

/* Function to print reverse of the passed string */
void reverse(char *str)
{
   if(*str)
   {
       reverse(str+1);
       printf("%c", *str);
   }
}

int main() 
{
   char a[] = "Tech Stuff for Interview";
   reverse(a);
   return 0;
}

Explanation: Recursive function (reverse) takes string pointer (str) as input and calls itself with next location to passed pointer (str+1). Recursion continues this way, when pointer reaches ‘\0′, all functions accumulated in stack print char at passed location (str) and return one by one.

Programme for getting IP address information

# C Programme for Getting IP Address Information Using Network Interfacing

#include <stdio.h>
#include <string.h> /* for strncpy */
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <netinet/in.h>
#include <net/if.h>

int main()
{
 int fd;
 struct ifreq ifr;

 fd = socket(AF_INET, SOCK_DGRAM, 0);

 /* I want to get an IPv4 IP address */
 ifr.ifr_addr.sa_family = AF_INET;

 /* I want IP address attached to "eth0" */
 strncpy(ifr.ifr_name, "eth0", IFNAMSIZ-1);

 ioctl(fd, SIOCGIFADDR, &ifr);

 close(fd);

 /* display result */
 printf("%s\n", inet_ntoa(((struct sockaddr_in *)&ifr.ifr_addr)->sin_addr));

 return 0;
}