Parameter Passing for Subroutines

In the previous chapter, we discussed subroutines in general. We discovered that we can use subroutines to share and reuse code in a program. We also discovered a limitation: we have to rely on global variables to let the code invoking the subroutine communicate with the invoked subroutine.

This chapter presents the concept of ``parameters''. Parameters is a powerful concept that allows a clean, elegant and flexible linkage between a subroutine and the code that invokes it.