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Adding comments to code for human understanding

From: Foundations of Programming: Fundamentals

Video: Adding comments to code for human understanding

Once you've written more than a handful of lines of JavaScript or indeed any programming language, you are going to want to start adding comments to your code so it can remind you what you were trying to do a week ago or six months ago or a year ago. You add comments in JavaScript the same way as in the other C-based languages. The most simplest way of doing this is to actually write a line that begins with two forward slashes. Anything after two forward slashes will be ignored. So this is a single line comment.

Adding comments to code for human understanding

Once you've written more than a handful of lines of JavaScript or indeed any programming language, you are going to want to start adding comments to your code so it can remind you what you were trying to do a week ago or six months ago or a year ago. You add comments in JavaScript the same way as in the other C-based languages. The most simplest way of doing this is to actually write a line that begins with two forward slashes. Anything after two forward slashes will be ignored. So this is a single line comment.

As soon as we leave that line, the rest of our code will be processed as normal. You can actually use those two forward slashes and even put them after an existing line, but it is more common to put them before the code that they are meant to be applying to. So if I was trying to split up some of my code here, I might say that this section was my Boolean variables and this previous one was my numeric variables. Obviously, these are pretty sel explanatory here.

It's quite common that you will also see a blank line before the comment because it just makes it much more visible. Now what you can also do are create what are called multi-line comments. While we could use multiple lines just with two forward slashes on it, what we can also do is use a /* and now everything is a comment until we get to */.

I only tend to use the multiple line format to comment out large chunks of code when I'm testing. Everywhere else I tend to use the single-line format just with the two forward slashes and that's what I'll be using for most of this course.

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This video is part of

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Foundations of Programming: Fundamentals

61 video lessons · 93545 viewers

Simon Allardice
Author

 
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  1. 4m 15s
    1. Welcome
      1m 17s
    2. Making the most of this course
      2m 8s
    3. Using the exercise files
      50s
  2. 22m 11s
    1. What is programming?
      5m 45s
    2. What is a programming language?
      4m 48s
    3. Writing source code
      5m 34s
    4. Compiled and interpreted languages
      6m 4s
  3. 16m 29s
    1. Why JavaScript?
      4m 45s
    2. Creating your first program in JavaScript
      6m 54s
    3. Requesting input
      4m 50s
  4. 31m 38s
    1. Introduction to variables and data types
      5m 16s
    2. Understanding strong, weak, and duck-typed languages
      3m 51s
    3. Working with numbers
      5m 4s
    4. Using characters and strings
      4m 5s
    5. Working with operators
      4m 47s
    6. Properly using white space
      6m 46s
    7. Adding comments to code for human understanding
      1m 49s
  5. 24m 48s
    1. Building with the if statement
      7m 35s
    2. Working with complex conditions
      4m 9s
    3. Setting comparison operators
      6m 59s
    4. Using the switch statement
      6m 5s
  6. 17m 54s
    1. Breaking your code apart
      4m 1s
    2. Creating and calling functions
      2m 56s
    3. Setting parameters and arguments
      6m 7s
    4. Understanding variable scope
      2m 23s
    5. Splitting code into different files
      2m 27s
  7. 13m 31s
    1. Introduction to iteration
      4m 28s
    2. Writing a while statement
      5m 24s
    3. Creating a for loop
      3m 39s
  8. 19m 28s
    1. Cleaning up with string concatenation
      4m 30s
    2. Finding patterns in strings
      8m 3s
    3. Introduction to regular expressions
      6m 55s
  9. 19m 58s
    1. Working with arrays
      5m 46s
    2. Array behavior
      5m 29s
    3. Iterating through collections
      5m 18s
    4. Collections in other languages
      3m 25s
  10. 10m 50s
    1. Programming style
      5m 55s
    2. Writing pseudocode
      4m 55s
  11. 25m 55s
    1. Input/output and persistence
      3m 6s
    2. Reading and writing from the DOM
      8m 11s
    3. Event driven programming
      7m 47s
    4. Introduction to file I/O
      6m 51s
  12. 24m 25s
    1. Introduction to debugging
      5m 57s
    2. Tracing through a section of code
      7m 5s
    3. Understanding error messages
      3m 21s
    4. Using debuggers
      8m 2s
  13. 14m 16s
    1. Introduction to object-oriented languages
      5m 18s
    2. Using classes and objects
      6m 28s
    3. Reviewing object-oriented languages
      2m 30s
  14. 11m 14s
    1. Memory management across languages
      5m 11s
    2. Introduction to algorithms
      4m 2s
    3. Introduction to multithreading
      2m 1s
  15. 29m 20s
    1. Introduction to languages
      1m 42s
    2. C-based languages
      4m 40s
    3. The Java world
      3m 13s
    4. .NET languages: C# and Visual Basic .NET
      6m 17s
    5. Ruby
      3m 4s
    6. Python
      2m 56s
    7. Objective-C
      4m 3s
    8. Libraries and frameworks
      3m 25s
  16. 1m 2s
    1. Where to go from here
      1m 2s

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