Getting started with structures

#include<stdio.h>
struct date
{
 int day;
 int month;
 int year;
}x,y;
int main()
{
 struct date today;
 today=(struct date){13,12,2018};
 struct date day;
 day=today;
 day.year=2017;
 printf("%i-%i-%i\n",today.year,today.month,today.day);
 printf("%i-%i-%i",day.year,day.month,day.day);
 return 0;
}