How to manage date in C

date_example.c

#include <time.h>
#include <stdio.h>
 
 
int main (void) {
  time_t cur;
  time_t next;
  struct tm curtime;
  struct tm nexttime;
 
  curtime.tm_hour = 01;
  curtime.tm_min = 0;
  curtime.tm_sec = 0;
  curtime.tm_mday = 27;
  curtime.tm_mon = 1;
  curtime.tm_year = 2003-1900;
  /* Normalize time (fill missing info)*/
  cur = mktime(&curtime);
 
  nexttime = curtime;
  next = mktime(&nexttime);
  /* From February, 27th to March 1st*/
  next = cur + 2*24*3600;
 
  //fputs (asctime (&curtime), stdout);
  //fputs (asctime (&nexttime), stdout);
  fputs (ctime (&cur), stdout);
  fputs (ctime (&next), stdout);
  //printf("%.f %d\n", difftime(next, cur), next-cur);
  return 0;
}
 
 
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Result :
 
Thu Feb 27 01:00:00 2003
Sat Mar  1 01:00:00 2003