And you think system administrators are grumpy ? :-)

happy_birtday.c

#include <sys/sysinfo.h>
#include <stdio.h>

int seconds2days(int seconds){
  return seconds/(60*60*24);
}

int days2year(int days){
  return days/365;
}


int main(argc){

  struct sysinfo info;
  int uptime, age, exitstatus=0;

  sysinfo(&info);
  uptime = seconds2days((int) info.uptime);
  uptime = 427;
  age = days2year(uptime);

  if (uptime < 1){
    printf("Im a new born!\n");
    }
  else if((uptime % 365) == 0 )
    {
    printf("Happy '%d' birth day to you!\n", age);
    exitstatus=1;
    }
  else
    {
    printf("Im '%d' year , '%d' day old!\n", age, uptime%365);
    }

  return exitstatus;
}