Chapter 5. Arguments: passing data to functions

This chapter covers

  • Defining functions with parameters, ready to accept data
  • Calling functions, passing in data with arguments

Functions are an essential means of organization; you write them once and use them many times. But so far, your functions have been tied to the values of variables around them. It’s time to set your functions free, letting them name their own variables and passing them the data they need.

5.1. Function reuse and versatility

The functions you’ve used up to now have relied on variables declared and assigned values elsewhere in the program. In the following listing, the showMessage function relies on a variable called message, declared outside the function definition. ...

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