Попробуйте параметр ширины в printf.Например:
printf("%8s%8s%8s%12s %s\n", "Pid","Port","Proto","Status","Process");
printf("%8d%8d%8s%12s %s\n", 10, 200, "TCP", "LISTEN", "httpd.exe");
printf("%8d%8d%8s%12s %s\n", 101, 20100, "TCP", "ESTABLISHED", "svchost.exe");