This section demonstrates the use of a C++ parser with a simple but complete example. This example should be available on your system, ready to compile, in the directory examples/c++/calc++. It focuses on the use of Bison, therefore the design of the various C++ classes is very naive: no accessors, no encapsulation of members etc. We will use a Lex scanner, and more precisely, a Flex scanner, to demonstrate the various interactions. A hand-written scanner is actually easier to interface with.