Simple types

For example, we sometimes refer to the classes in components like String(3C++) and Time(3C++) (or the components themselves, when we are feeling too lazy to make careful distinctions) as simple types because of their similarity to built-in integral types like int. They provide (conceptually) simple objects without any inner structure. The following example illustrates the use of the types in Time(3C++); do you see the similarity to int?

       #include <Time.h>
       ...
       Duration d;
       Time t1,t2;
       ...
       d = t2 - t1;