390: Sidetrip

All the programs in this chapter define global arrays of cylinder objects. None of them happen to define a default constructor for cylinder objects, but as you learned in Segment 180, the C++ compiler defines a default constructor if you do not.

When, you might ask, do your C++ programs run the default constructors for objects in arrays? Here are the answers:

• The constructors for global arrays of class objects are activated at run time, just before C++ runs the main function.
• The constructors for local arrays of class objects are activated at run time, when the corresponding function is entered.