Karel Python - Commenting Code
Summary
TLDRThis video script emphasizes the importance of code commenting for readability and maintainability. It distinguishes between multi-line and single-line comments, illustrating how to use them effectively. The script advocates for the inclusion of preconditions and postconditions in function comments to enhance understanding. It provides an example using a 'Carol' program, demonstrating how to document program functionality and function behavior, encouraging viewers to practice commenting in their code.
Takeaways
- đ Code commenting is essential for good programming style, making the code readable and understandable to others.
- đ The dual importance of functionality and style in programming: the program must work and be clear to others.
- đ Comments serve as notes in plain English to explain what the code is doing, aiding in understanding by both the original coder and others.
- đ„ Comments are crucial for collaborative coding environments, as they help team members understand each other's code.
- đ There are two types of comments: multi-line comments, enclosed by triple double quotes, and single-line comments, started with a hashtag.
- âïž Multi-line comments are used for longer explanations and are ignored by the computer until the closing triple double quotes.
- âïž Single-line comments are used for brief notes and are ignored from the hashtag to the end of the line.
- đ Precondition and postcondition are key elements to include in function comments, explaining the state before and after the function is called.
- đ ïž Good commenting practice involves defining what the program does at the start with a multi-line comment and detailing functions with preconditions and postconditions.
- đŻ Use comments to guide the reader through the logic and purpose of the code, enhancing maintainability and readability.
- đĄ Encourage experimentation with commenting to improve coding style and ensure that code remains understandable over time.
Q & A
What are the two main aspects of writing a program according to the video?
-The two main aspects of writing a program are functionality, which determines if the program works and does what it's supposed to, and style, which assesses if the program is clear, readable, and makes sense to others.
Why is it important to have good style in code?
-Good style in code is important because it makes the program clear to others, ensuring that the code can be read and understood by other programmers, which is crucial for collaboration and maintenance over time.
What role do comments play in writing programs with good style?
-Comments play a crucial role in writing programs with good style as they allow programmers to leave notes about what the code is doing in plain English, aiding in understanding and collaboration among team members.
What are the two types of comments mentioned in the video?
-The two types of comments mentioned in the video are multi-line comments, which are enclosed by three double quotes, and single-line comments, which start with a hashtag.
How does a multi-line comment start and end in the video's context?
-A multi-line comment starts with three double quotes and ends with another set of three double quotes. Everything between the two sets is ignored by the computer.
What is the purpose of a single-line comment in code?
-A single-line comment is used to ignore a specific line of code from being executed by the computer. It starts with a hashtag and the comment ends automatically at the end of the line.
What should be included in comments according to the video?
-According to the video, comments should include preconditions and postconditions of a function, which are the assumptions made before the function is called and what should be true after the function is called, respectively.
Can you provide an example of a precondition and postcondition mentioned in the video?
-An example of a precondition mentioned in the video is that Carol has jumped the last hurdle and is facing east before the 'run to finish' function is called. The postcondition is that Carol has reached the finish line after the function execution.
How does commenting help in a team setting?
-Commenting helps in a team setting by providing clarity on the code's purpose and functionality, assisting team members in understanding the code's intent and logic without needing to decipher the code itself.
What is the significance of commenting on the long-term maintainability of code?
-Commenting is significant for long-term maintainability of code as it allows future developers, including the original programmer, to quickly grasp the code's purpose and functionality, facilitating easier updates and debugging.
How does the video suggest documenting the program's purpose and functions?
-The video suggests using multi-line comments for documenting the program's purpose by explaining what the program does, and using both multi-line and single-line comments to document functions, including their preconditions and postconditions.
Outlines
đ Importance of Code Commenting
The first paragraph emphasizes the significance of not only making a program functional but also ensuring it has a good style, which includes writing clear and readable code for others to understand. It introduces the concept of comments as a means to leave notes about the code's purpose in plain English, highlighting the importance of comments in collaborative coding environments. It also differentiates between two types of comments: multi-line comments, which use triple double quotes, and single-line comments, which start with a hashtag.
đšïž Types of Comments in Programming
This paragraph delves into the specifics of how to comment in code, explaining the syntax for creating multi-line comments using triple double quotes and single-line comments using hashtags. It clarifies that the computer ignores everything within the triple double quotes and anything following a hashtag on the same line. The paragraph also touches on the content that should be included in comments, such as preconditions and postconditions of functions, which are essential for understanding the assumptions and expected outcomes of the code.
đ ïž Demonstrating Comments in a Sample Program
The final paragraph provides a practical example of how to apply comments in a coding environment, using a program named 'Carol' as a reference. It illustrates the use of multi-line comments to describe the overall purpose of the program and single-line comments to explain specific actions within the code. The paragraph also discusses the importance of documenting preconditions and postconditions for functions, giving a concrete example of how to comment on a function that makes Carol run to the finish line after jumping hurdles.
Mindmap
Keywords
đĄCommenting
đĄProgramming Style
đĄFunctionality
đĄCode Readability
đĄPreconditions
đĄPostconditions
đĄMulti-line Comments
đĄSingle-line Comments
đĄTeams and Groups
đĄCarol
Highlights
The video emphasizes the importance of code commenting for style and readability.
Code functionality and style are both essential components of programming.
Well-commented code is crucial for understanding and maintenance by others.
Comments serve as notes in plain English explaining what the code is doing.
Coding is often a collaborative effort, necessitating clear communication through comments.
There are two types of comments: multi-line and single-line.
Multi-line comments are created using three double quotes and can span multiple lines.
Single-line comments use the hashtag and are ignored after the hashtag until the end of the line.
Preconditions and postconditions of a function should be described in comments.
Preconditions are assumptions that must be true before a function is called.
Postconditions define the expected state after the function execution.
Demonstration of commenting in an editor with a sample program about Carol.
The program description is provided within multi-line comments for clarity.
Function definitions include preconditions and postconditions for better understanding.
An example of a single-line comment explaining a specific action in the code.
The video encourages viewers to practice commenting in their own code.
The video concludes by inviting viewers to explore and experiment with commenting.
Transcripts
hi in this video we're gonna look at
commenting your code so you've got to
have good style there are two parts to
writing a program functionality does it
work does it do what it's supposed to
there's also a style component is your
program clear and readable and does it
make sense to others it's not enough for
your program to work it also has to have
good style a good style means that
you've broken down the problem in a
reasonable way and your code is clear to
others it's a very important part of
programming and we want to be able to
write readable code code that others can
read and understand for years to come an
important part of writing programs with
good style is comments so introducing
comments comments are a way for you to
leave notes about what your code is
doing in plain English so why comment
although code is run by computers it's
read by other people coding is not a
solo exercise coding is usually done in
teams in groups so comments help others
and you understand what your code is
trying to do so how do we comment there
are two different types of comments
multi-line comments and single line
comments so create a multi-line comment
we use three double quotes then leave
comments on the next lines to end a
multi-line comment we use another set of
three double quotes everything between
the two sets of three double quotes is
ignored by the computer we can also do
single line comments these are done by
using hashtags on any line once the
computer sees the hashtag it'll ignore
the remainder of that line of code but
start reading automatically on the next
line notice that a single line comment
doesn't have anything to end the comment
the comment just ends automatically at
the end of the line so what exactly do
we communicate in a comment one of the
most important things we can comment
about are the preconditions and
postconditions of a function
preconditions are the assumptions that
we make and what must be true before the
function is called the post conditions
are what should be true after the
function is called so for all of our
functions we should write preconditions
and post
conditions so let's take a look at some
comments in the editor okay so let's
take a look at comments in Carol so
we're gonna start off by commenting this
her dota Carol the first thing we want
to do is kind of define what our program
is talking about so we're going to put
in our two sets of triple double quotes
and then kind of talk about what the
program does we're gonna say this
program has Carol start bottom and jump
two hurdles before running to the finish
okay so something like that it tells us
exactly what this programs supposed to
do okay then we can define our functions
so again we'll use two sets of triple
double quotes okay
and so this run to finish we'll say this
function as Carol run to the finish line
after jumping the last hurdle now what
we want to do with functions is we want
to have our precondition in a post
condition so I'm going to say
precondition is and that is precone the
precondition is what condition Carol
will be in at the start is we're going
to say Carol has jumped the last hurdle
and is facing east okay and the post
condition tells us exactly what
condition Carol is going to be in at the
end of the function so we're gonna say
Carol has reached the finish line okay
and we can go ahead and do the same
thing for these others I'm gonna leave
those for you right
now but what I want to do is just show
you how we can do a single line comment
so again if we do a single line comment
we just start with a hashtag and we can
say this program will have Carol jump
have Carol jump two hurdles so again we
can do single line comments like that we
can do multi-line comments like that you
can see the rest of the comments in the
examples and now it's time for you to
play around
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