Sams Teach Yourself PHP, MySQL® and Apache All in One, Fifth Edition

Chapter 7. Working with Functions

In this chapter, you learn the following:

• How to define and call functions from within your scripts

• How to pass values to functions and receive values in return

• How to call a function dynamically using a string stored in a variable

• How to access global variables from within a function

• How to give a function a “memory”

• How to pass data to functions by reference

• How to verify that a function exists before calling it

Functions are at the heart of a well-organized script and make your code easy to read and reuse. No large project would be manageable without them because the problem of repetitive code would bog down the development process. Throughout this chapter, you investigate functions and learn ...