Need to define a new type in "C."
New type is "datetime."
Use two variables: birthDate, tempdate

If I use birthdate= tempdate + 20;

how can I assign 20 to be:
minutes
years
seconds
days

You can use structures

struct Dtime
{
       int mins;
       int years;
       int days;
};

The to declare a variable:

dtime datetime;

And to assig values.

datetime.min = 10;
datetime.year = 2004;

Just use the var_name.member and you can do anything to them as would do to a normal int, char etc.