Chapter 6: Functions

overhead view of arcade games with people playing the games — **Figure 6.1** credit: modification of work "IMG_3037", by Jay Roc/Flickr, Public Domain

Functions are the next step toward creating optimized code as a software developer. If the same block of code is reused repeatedly, a function allows the programmer to write the block of code once, name the block, and use the code as many times as needed by calling the block by name. Functions can read in values and return values to perform tasks, including complex calculations.

Like branching statements discussed in the Decisions chapter, functions allow different paths of execution through a program, and this chapter discusses control flow and the scope of variables in more detail.

Adapted from Introduction to Python Programming by OpenStax (openstax.org), licensed under CC BY-NC-SA 4.0. Changes were made. License: CC-BY-NC-SA-4.0.