Programming

$ cat sock.c
#include <stdio.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

main(){
        struct in_addr a;
        int i;
        int incr;
        incr=inet_addr("255.10.20.30") - inet_addr("254.10.20.30");

        printf("1st incr = %d \n", incr);
        incr=inet_addr("255.11.20.30") - inet_addr("255.10.20.30");
        printf("2nd incr = %d \n", incr);
        incr=inet_addr("255.10.21.30") - inet_addr("255.10.20.30");
        printf("3rd incr = %d \n", incr);
        incr=inet_addr("255.10.20.31") - inet_addr("255.10.20.30");
        printf("4th incr = %d \n", incr);

        a.s_addr=inet_addr("255.10.20.30");
        for(i=0;i<5;i++) {
                printf("%s\n", inet_ntoa((struct in_addr) a));
                a.s_addr += 65536;
        }
        exit(0);
}
$ ./sock
1st incr = 1
2nd incr = 256
3rd incr = 65536
4th incr = 16777216
255.10.20.30
255.10.21.30
255.10.22.30
255.10.23.30
255.10.24.30
$