Basics of Iteration

Let’s talk about the basics of iteration. In this episode, you will learn about iteration as it is a key process in programming.

Your key takeaways are:

• Iteration is repeating a sequence
• It’s a loop
• Separate the iteration functionality from the container

Study Notes

Here’s the primary question: How do you iterate through a container? How do you “say or do a thing again or again and again” (Merriam-Webster.)

What is Iteration?

Per Merriam-Webster:

• the action or a process of iterating or repeating:
  • as a procedure in which repetition of a sequence of operations yields results successively closer to a desired result
  • the repetition of a sequence of computer instructions a specified number of times or until a condition is met — compare recursion
• one execution of a sequence of operations or instructions in an iteration

It’s a loop!

Iterating Through an Array

1. Set the pointer position to 0.
2. Fetch the key and data (value.)
3. Do the work.
4. When done, number of elements > pointer position?
   1. If yes, then increment pointer position.
   2. If no, stop.
5. Go to step 2 (repeat.)

What’s needed to iterate a container?

• Pointer in the collection
• Functionality to do the iteration sequencing
  • Where should this functionality be?
  • Should it be separate or a part of the collection?

Terminology

Coupling: “the act of combining two things.”

De-coupling:

• the act of unlinking two things
• separating two things from one another

Why?:

• you can swap out implementation
• less complexity
• promotes reuse
• a change in one module does not cause a ripple effect

Congratulations, you just learned a key software and quality principle!