Scant does not print: it reads a value from the user and converts it to an internal form.
To output the date, use print, not scanf.
I'm not a big fan of scanf at the best of times, it's generally better to read a string, and then use sscanf to parse that, as it's a lot easier to debug, and better for error reporting as well.
But the printf for as date is pretty simple:
printf("%02d-%02d-%04d", day, month, year);