About Linux inet_addr Inet_aton inet_ntoa functions and Inet_pton inet_ntop functions __oracle

#include <netdb.h>
#include <stdio.h>
#include <sys/types.h>
#include <stdlib.h >
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>

int Main (int argc, char * argv[])
{
    if (argc!= 2)
    {
        printf ("Usage:%s <ip>\n", argv[0]);
        Exit (0);
    }

    struct Hostent * hostent = gethostbyname (argv[1));    
    printf ("%s\n", hostent->h_name);

    in_addr_t ADR = INET_ADDR (hostent->h_name);
    int i = 0;
    for (i = 0; i < 4; i++)
    {
        printf ("%x", * (((char*) &adr) + i);
    }
    printf ("\ n");
    printf ("0x%x\n", ADR);


    struct IN_ADDR adrr;
    Inet_aton (Hostent->h_name, &ADRR);    
    printf ("0x%x\n", adrr.s_addr);

    char * str = INET_NTOA (ADRR);
    printf ("str:%s\n", str);
    return 0;
}

#include <stdio.h>
#include <arpa/inet.h>

int main ()
{
    struct in_addr addr;
    if (Inet_pton (af_inet, "192.168.159.128", &addr))
    {
        printf ("0x%x\n", addr.s_addr);
    }

    Char strip[100];
    if (Inet_ntop (af_inet, &addr,strip, sizeof (strip))
    {
        printf ("%s\n", strip);
    }
    

    return 0;
}