Data stored in a struct or union is accessed member by member. So if you needed to copy one object to another, with both having the same type (a user-defined struct, for example), you would need to do so member by member. If one happens to be a struct, then it too must be copied member by member.
Accessing a member of a struct or union is accomplished in the following way:
This code assumes that you have defined a variable of a specific type in variable_name, and that it is a struct or union. You’ll learn about the specific concerns of union data member access later; for now, let’s look at structs specifically.
You saw this originally in the definition of the data type tm for use with the various standard ...