Obtain the source code for the PFArrayD class and the demonstration program from Displays 11.10 , 10.11 , and 10.12. Modify this program to use namespaces and separate compilation. Put the class definition and other function declarations in one file. Place the implementations in a separate file. Distribute the namespace definition across the two files. Place the demonstration program in a third file. To provide access to names in namespaces, you may use local using declarations such as

using std::cout;

or use local using directives such as

using namespace std;

inside a block, or qualify names using the names of namespaces, such as std::cout. You may not use global namespace directives such as the following which are not in a block and apply to the entire file:

using namespace std;