HP aC++/HP C A.06.25 Programmer's Guide

} // for this simple
// example
void C::operator delete[ ] (void *p)
{
cout << “Use operator delete[ ] from class C\n”;
// here, real usage would include deallocation
::operator delete[ ] (p); // global operator
} // for this simple
// example
int main()
{
C *p;
p = new C[10];
delete[ ] p;
}
Notice that the new operator takes a class with an array specifier as an argument. The
compiler uses the class and array dimension to provide the size_t argument. In the
example above, the argument provided is ten times the size of a class C object. Also,
the operator must return a void* which the compiler converts to the class type. The
void constructor for the class (if one exists) is invoked to initialize the elements in the
array.
Multidimensional arrays can be allocated and deallocated with these operators. The
operator is used with several array dimensions, and the compiler provides the size_t
argument which is the space required for the entire array. For example:
// call C::operator new[ ] ( ) with
// an argument of 10 * 20 * sizeof(C)
p = new C [10] [20];
Additional arguments can be provided to this operator new just as for the operator for
single objects. In this way, the operator can be overloaded in a class. The additional
arguments can be used by the storage allocation scheme for additional storage
management.
The global new and delete for both arrays and single objects are provided in the
Standard C++ Library. This library also provides a version of new for arrays and single
objects that takes a second void* argument and constructs the object at that address.
Standard Exception Classes
Classes are provided in the Standard C++ Library to report program errors. These
classes are declared in the <stdexcept> header. All of these classes inherit from a
common base class named exception. The two classes logic_error and
runtime_error inherit from exception and serve as base classes for more specific
errors.
198 Standardizing Your Code