This C Program displays the IP Address of the system.
Here is source code of the C Program to display the IP Address of the system. The C program is successfully compiled and run on a Linux system. The program output is also shown below.

/*
* C Program to Get IP Address
*/
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <netinet/in.h>
#include <net/if.h>
#include <unistd.h>
#include <arpa/inet.h>

int main()
{
int n;
struct ifreq ifr;
char array[] = "eth0";

n = socket(AF_INET, SOCK_DGRAM, 0);
//Type of address to retrieve - IPv4 IP address
ifr.ifr_addr.sa_family = AF_INET;
//Copy the interface name in the ifreq structure
strncpy(ifr.ifr_name , array , IFNAMSIZ - 1);
ioctl(n, SIOCGIFADDR, &ifr);
close(n);
//display result
printf("IP Address is %s - %s\n" , array , inet_ntoa(( (struct sockaddr_in *)&ifr.ifr_addr )->sin_addr) );
return 0;
}

$ cc pgm56.c
$ a.out
IP Address is eth0 - 192.168.225.135