Master Pointers in C: 10X Your C Coding!
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- Опубликовано: 6 июн 2024
- Pointer basics, indirection, void pointers, pointers to pointers, function pointers, callbacks and much more in this comprehensive introduction to pointers. For information on my book, "Secrets of the Autistic Millionaire": amzn.to/3diQILq
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This is a revised edit (shorter and without intro) of the video from several days ago!
As always, all content and opinions are mine only, (c) 2022 Plummer's Software LLC. 
Наука
My dad taught me about pointers using index registers in assembler.
Sounds like IBM mainframe HLASM. I've been doing that for a little over 40 years. Although I vaguely remember some 8 bit computers which had an index register. I don't know x86.
I used indirect addressing in assembler for some years before I realised I was using pointers, when I did a Pascal course around 1984.
I would have struggled less in the beginning if someone would have told me that a pointer is like 6502 zero page!
@@DavesGarageI programmed the 6502 way back in the 80s, but I didn't have an assembler. I did everything directly in hex op codes etc. But that stuff definitely helped me later with pointers in C i.e. they're just memory addresses as you said.
Dad's should teach assembly language to their children. I think of it like the Latin of computer languages. You learn about how the computer actually works and appreciate all of the things that come along for free with the HLLs that you will use. You also see pointers in things like the aptly named Stack Pointer and the Instruction Pointer. You also see function pointers in vector tables. Assembly is cumbersome but you learn so much by doing just a little bit.
These three sentences solved the big problem I was having when learning pointers: "Depending on the size and complexity of the house structure that could be an expensive and wasteful operation. Why is it wasteful? Well because just like in real life there's no reason to bring your house to the appraiser for an appraisal the appraiser comes to you."
I was always so confused as to why you would use pointers when you could just carry the whole object around. But because it copies the entire house variable, which is often more data than a 8 byte pointer, this makes it efficient to use on any item that is larger than the size of a pointer. Thanks a ton!
That analogy between memory address and the address of a house is great! I used to make similar comparisons when teaching C to students and it really seemed to help make it click for them.
I'm 12 years into programming now... And i just understood the concept now, with that analoy :D
as if you never heard that analogy before. that analogy was in every tutorial I've seen.
You look exactly like a person who would teach me about pointers. Just like a Wizard NPC in games.
Dave, i have been coding in C since 1980 and have, many times, tried with variable success to explain pointers to newbies. This video is clearer and more concise then my best efforts. Going forward I'm just going to refer newbies to this. Thanks.
Hope it helps others!
This is the most amazingly coherent, clear and informative explanation of pointers I have seen in 14 years since I started programming in C and C++. This is beyond fantastic omg please continue. :)
i was a TA for an intro to C class, and the house example was what i used to describe pointers to people really confused about them. glad to see that you are using a similar example here! i feel that the easiest way to describe technical concepts to people who are confused about them(or have no technical experience/knowledge) is to use a real world analogy, even if it oversimplifies what is actually going on. once they understand the analogy and how it relates to the technical concept, then they can get to the nitty gritty of understanding the technical details behind the concept
Hi Dave, I discovered your channel a few days ago and enjoyed some windows related vids; today I wanted to improve my understanding of C pointers and, voila, here you are again! I looked at some other tutorials, but yours is definitely the best! I really love your style! Keep up your great work; it's pure gold! ❤
Wow, 40 years ago I was still programming Fortran and had never heard of object oriented programming. At the time I was designing a production program to run various tests on pacemakers and since all the tests had some shared behavior (like limits checking, saving results to a database, printing results, etc.), I decided to create a large common block array that was indexed by something I called a "test number" then functions could do what they needed with just a test number. One huge advantage was that I could configure what tests to run and what limits to use and units to report with a big constant array at the top of the code. This meant that when a new test specification came out, usually all I had to do was to change the constant array and no code change was required. Later on in my career my SW boss told me I had created Object Oriented Fortran. Interesting - I was just a young "lazy" programmer trying to find a way to do more with less code to develop, debug, and validate. Also, being ADD, my brain worked faster than my fingers.
Haha, all programmers are lazy; this is what drives the development of technologies, languages and so on!
@@tangiblewaves3581 well i agree but i dont agree, i think we always find shorter ways to do things and yes we develop wicked tech from it, but programming its self can be very intensive / labor intensive. And takes a lat of work even to learn, so i get what your saying, but programmers are just like any trade (plumbers, electricians) and just like those trades look for better ways. I have a family full of trades, and they are full of unique (what i would call lazy) ways to fix stuff but it works and they have good solid reputations for the work they do, sometimes its those ways that make a completely new product that works 10x what the previous method is, but it takes knowledge and the skill to think it through (and sometimes the balls to apply the fix lol and hope it works.) just like them, programmers, designers and scientist need to sometimes "go back to simple" in order to step forward. All that said... i have seen lazy programmers and lazy plumbers. so i think the ratio is likely the same in terms of avoidance of physical labor. o7
@@theMaizeOfficial exactly, and if you want to code proffessional, you also need some good amount of discipline to code even when you have a bad day or are tired.
Cool story.
A good programmer is that who will spend 3 hour of his time to automate a one time task that requires half an hour to be made manually.
Good video, Dave. I also have been working in C/C++ for about 40 years, including work for some notable compiler vendors such as C86, Zortech C++, and GCC (via Cygnus).
This was IMO an uncommonly clear and well-organized presentation. Was impressed that you had time to include pointer-to-functions in this 14-minute overview.
Perhaps you might have mentioned the precise prototype matching required to do real-world useful work involving pointer-to-functions; and in particular, how judicious use usually warrants declaring a typedef for a particular group of related pointers-to-functions.
I've been (slowly) learning C as my starting language just for fun. Pointers has given me many headaches and I still can't completely get a picture in my head of how they work. I wish sometimes that they had a special name or different symbol, maybe that would've made it easier. But you mentioned a few things (that I had to listen to 3-4 times) that gave me some better insight, so maybe one day. Thanks!
Making a drawing of it often helps a lot.
Hang in there! You'll understand them 👍
C and C++ learning is like this: you learn the basics and start writing. Then you want to do more or understand someone else's code, at that point you go through 3 to 6 months of FOG where you don't quite get it, but you keep trying. The good news is once you get past that, you become a decent programmer.
@@newmonengineering I basically set out to make a reasonably simple game and by using reference code from others or books I've managed to piece things together bit by bit. By interpreting compiler errors I've managed to kind of get a feeling for when it's in need of a pointer or not. So I definitely know more now than half a year ago luckily :)
I think C started a bad pattern for working with pointers because you declare one with the same symbol you use to dereference one. That said the arrow operator has some, as of yet untapped, potential for conveying ownership semantics needed for automated resource management (at the cost of the control C devs freak over :p)
Wow. This made a whole lot more sense to me by the end. Thanks Dave!
Thanks for making this video! I still remember the exact ‘ahah’ moment (two decades ago in freshman cs) when I grokked c memory (pointers, arrays, structures). Learning how c handles memory really helped me understand how computers work.
Hands down one of the best and concise explanations of pointers! It seems to all click in place after using and avoiding them all these years!!!
I have always struggled with this. Dave, your explanation is the best I've ever heard and it worked for me! Like you say "it clicked"!
Thanks! Very Helpful. You explained some things that C++ books that I have read have overlooked. Like ..... The reason why we even need to use pointers to begin with. I hope to see more content like this.
You can also subtract a end pointer from a start pointer to get the length of data or string.
As for void pointer if you use the same format for all your structs then a uin64_t in the beginning can be used to identify the data type.
Pointers were so logical and intuitive for me. When I was first learning C++ I was coming from having played around with languages that didn't have dynamic allocation, I didn't know what dynamic allocation was at the time but I had been frustrated in numerous projects I had made that I couldn't make new variables at runtime. So when I first read an example of malloc and using a pointer I immediately put down the book (before even reading the explanation of the example) because I had recognized it as the solution to what I had wanted for so long and wrote a linked list (not that I knew that it was a linked list at the time) to verify that it could do exactly what I had hoped it could, and it worked. I was so excited, the possibilities of pointers were limitless in my eyes and I messed around with them for most of the rest of the day.
When I finally got back to reading the book that I was using to learn C++ I was a little disappointed to learn that everything I thought I had created to use pointers for was pretty much covered in the next chapter, but I was glad that at least I had understood them well enough that I could correctly extrapolate their uses without knowing much more than that they existed. It also turned out the example was only the first half of the program that only covered allocation, it wasn't until I turned the page to see the deallocation example and read the explanation for it that I realized all the horrors of memory leaks and how many I must have created that day 😉
"having played around with languages that didn't have dynamic allocation"
Cobol ?
@@IBelieveInCode Logo and Visual Basic, though I was very young at the time and no internet so I might just not have been aware if they actually did have that capability.
Honestly i don't have any problems at all understanding the concept of pointers, all that makes sense to me. What i don't understand, is when you want to use them
Maybe that is the right way to tech the concept, is to pose problems that require the indirection to do the job. A lot of things are easy if the person thinks it was their own idea or something they want rather than something imposed from outside. Get them to say for themselves "what I really need is some way to ..."
@@TehIdiotOne as said on this video, the most common use is with larger or variable data types like objects, it is much more efficient to point to the adress of an object than bring the entire object into memory, this is especially noteworthy in C++ when storing lists of large objects or integers, you just use the pointer and the -> operator and it is way more memory efficient. Plus, it allows for dynamic memory allocation which allows to manage what is and what isn't in memory at any given time
Let me speak from my heart =) This description was absolutely incredible! I wish I've had it about 5 years ago..
Thanks for your programming content! I have been a programmer for a while but nowadays information technology seems much too complex for me. I cannot code for real but I can follow your explanations and understand them. It's just I have problems memorizing them. So I consider your videos a source of sophisticated entertainment.
I started learning Turbo Pascal in the mid 90s, so for me pointers where never really hard to grasp as TP uses them too.
Once you have the concept in your head a pointer to an array of pointers becomes a natural thing to work with.
Great video!
We are that old, eh?
I first used pointers in Pascal on a mini computer in the mid 80s, and then Turbo Pascal in 1986, although I was also an assembler programmer before that, where you use pointers all the time but call it indirect addressing. Pascal taught me about structures.
Then I went onto C, but it was K&R, and I found the nomenclature hard to follow: it took me months to get proficient, not because I didn't understand the concepts, but because K&R C can be super impenetrable for a C noob. Thankfully ANSI C came along at just the right time, I re-wrote the K&R code I was maintaining in ANSI, and I've stuck with that ever since.
C remains my language of choice to this day, but mostly I'm a deeply embedded systems programmer and mixed signal hardware engineer, where C sits well, nice and close to the hardware. I dip into assembler still every now and again for those pinch points, but 99% is C.
@nezbrun872 I literally use Delphi for fun nowadays, with a free Community license. It's pretty fun tbh
Such a good video Dave, straight to the point. much love from Argentina!
Thanks Dave for revising my C concept. Last time when I did was solving exercise of K&R in 1 st year of graduation. Clap for your line "I am not here to sell anything".
I've been waiting for you to dive into programming like this... Did not disappoint. Bravo 👏👏👏👏
Very clear introduction to the most important things about pointers.
Remember struggling a lot with those when I started using C++.
Its a great video if you understand pointers but it fails to do the most important part of why people don't understand pointers. People don't understand pointers because they don't understand the problem they are solving.
The moment you understand how memory works, how data is stored/loaded in/from memory and what the cpu has to do differently depending on if you call by reference or by value is the moment you get pointers. The real explanation needed is not what pointers are but what problem they solve and why you need them.
Back when i was learning C i had a hard time wrapping my head around pointers until one day my boss took an houre to explain the difference. He showed me the assembler output of different scenarios with and without pointers and explained what happened on each line inside the cpu and memory and it just all made sense after that. It's not about what pointers are but what problem they solve and how.
Assembly is a lost art, but explains so much.
this
Yeah assembly could have explained it simply..
You have Registers, and direct/indirect addressing…
all registers can be pointers unless they all are general purpose registers
Then the addressing and instructions decide how we are representing the registers
LA R1,=A(0000) Load address of location where =A(0000) has been resolved in the executable, into Register 1
XC 4(256, R1), 4(R1) XOR 256 bytes starting from values pointed by R1 offset by +4 bytes with the same… (XOR of itself is 0 ie clearing all the bits/bytes at that location)
ST R1,INT32 Store value in R1 into location INT32
L R3,INT32 Load value at INT32 into R3
LA R4,INT32 Load absolute address of symbol INT32 into R4
ST R3, 0(R4) Store R3 into INT32 symbol location
INT32 DS 4F
Someone who knows assembly should be able to teach pointers in a better way
Thanks Dave!! I am learning C++ and pointers where the most challenging part. This was a great help.
This is really, really helpful. You have a talent for explaining things.
Thanks, Dave! This is what I'm talking about! Coverage of more advanced C/Cpp topics. Please keep up with explaining some applications where the topic-of-the-day is used. I will say again, your knowledge should be memorized in a book. I would buy two!
This video is exactly what I was looking for to help me improve my programming skills. Thank you for making it!⭐♥
I recently started teaching the introduction system's programming course at my university, and this should make for a great review resource going forward, thank you for this and the many great videos!
Thanks for this, Dave. I led the way you explained and the examples. I hope this C/C++ videos keep coming :)
Great video. Straight to the point, easy to follow along.
Thanks for the pointers, Dave!
Thank you so much for putting together such a great video on pointers. I’ve watched it twice and I plan to watch it three or four more times until I understand every single concept of gone over here. The function pointers are still a mystery to me how I would use those affectively
30 years ago I learned about pointers in C, and I’m grateful for this recap. Some things made more sense even now, after watching this, particularly the double indirection.
Holy mackrel
I don't think I ever rewatched a single video consequtivelt as this.
Sir, in 12 minutes, you explained pointers better than my professor in an hour and a half.
one of the best videos on this topic in my opinion. thank you!
Starting with C and fiddling with memory made understanding how more higher level language handle memory / what is passed by reference vs value.
Awesome !! I now understand pointers better than I ever had. Thanks
Man, I could have used such a good explanation 30 years ago!!
Thank you Dave!
That's a very nice refresher on pointers. Thank you!
Excellent! My best saga was creating a pointer to an array of functions (oh what fun) 😆
My experience with pointers came with my first programming being PDP-11 assembly (school) and later 6502. So dealing with them in 'C was very straightforward...after the syntax of course. I say that because your comment about 'decorating the variable' rather than the type, (int* x is not int *x) was my personal stumbling block.
Dear Dave, you said something really wonderful. When you want to learn C++ or C but your first language is Python, of course, it looks scary. That is what I can hear from a lot of students who are honestly scared to delve into low-level languages and learn how "motor" actually works. Since I am a child of the 80s, my first language was machine code and assembler for 8-bit CPUs. As such, I always try to explain things from that perspective, emphasizing memory and how the CPU "crawls" through it. Thank you for this episode. I truly believe it is important. Greetings from the Netherlands.
As a veteran assembler and C programmer of over 45 years, I can tell you that Python is scary to me. I seem to spend more time maintaining a working development environment than I do writing code in Python.
@@nezbrun872 That sounds kind of disgusting. I've never dived into Python. I started with C64 BASIC and jumped to machine code after that. A few years later when I got into college I got introduced to Pascal. After that I pretty much went into C, because I was fascinated with MUDs and wanted to learn how to run one and modify it.
I was once in a class where students first learned Visual Basic and then moved on to Java. And I can say that Dijkstra was right, learning this way actually harms students.
@@nezbrun872 Dear, I totally agree with you. You have less control on data flow. Young people who are using languages as Python, then just don't think about memory, about what is going on behind.They rely on some, what they call - libraries, but it is more like the whole Lego block, framework. For me library is part of the OS or what I build for myself (: I'm glad there are more people who feel the same. Thank you for sharing!
@@TheAndjelika ...and this is why my windows machine uses 7GB of memory after just booting....
Your video encouraged me to Go Pointers again! Thanks!
Two follow-up tips:
The & (address-of operator) is used when you want to turn the address value of something into a pointer. Second, you will sometimes see that asterisk * in different places between the type and the pointer name: e.g. int* a; int * a; int *a; int (*a); ... all of these are exactly the same. The whitespace doesn't mean anything in these examples. That took me forever to understand. Just try to be consistent in code.
int* should be the only way to write int pointer.. everything else should be banned 😄😄
To me it makes the most sense. The type is an "int pointer" so put it with the type name... I think it's confusing for beginners because it looks similar to the dereferencing syntax.
@@JamieT1986 yes, but then a declaration in 4:07 would create 2 pointers, not one. int * x, y is in actuality: int *x AND int y.
I agree it would be better to just have something like 'intP x, int y' and then it would be obvious what is a pointer and what isn't but we got stuck with a syntax that is efficient for writing, but hard for reading - somewhat opposite to Python's syntax.
@@vaakdemandante8772 int* x, y; is something I was a little skeptical about actually when I saw this. I never knew that's how it worked, and I forgot to test it myself. I will assume it's correct... but yeah that kinda screws it up! :)
"int \*num" is much better, the declaration in 4:07 is confusing if you use the "type\* var" version.
Edit: I used "\" sign cuz youtube comments converts asterisk to bold letters. lol
This^^^ i would say, find a style and stick to it, but as an OS and firmware dev the most common style i come across (and use personally) is this:
Type* var_name = ….whatever here….
Ex: int* pointer_to_integer = (int*)malloc(sizeof(int));
So the asterisk essentially lives right next to the type, with no whitespace between. This makes it clear that it is a POINTER of said type, in my example a pointer to an ‘int’
Using this style consistently makes reading and reasoning about pointers much less frustrating in my opinion.
Of course, then there is dereferencing a pointer to get the object’s value. In those cases common style i see and use is this, continuing with my int example:
int integer_variable = *pointer_to_integer;
So we use the asterisk right against the VARIABLE NAME to dereference it. The combination of sticking to these two basic style guidelines makes points way less messy.
Essentially, use the asterisk directly next to your type name when declaring a pointer variable, and right next to the variable name when de-referencing it. Hope this helps some of the less experienced!
Also, as a follow up, i think the example at 4:07 of
Int* x, y
Is a kind of poor example. It just isnt code that would fly in most (well maintained) C projects like the linux kernel for example. You want things to be CLEAR above all else, and so its not really much effort to be explicit with each variable declaration. The compiler can optimize for you if it is necessary or possible. Otherwise, be more verbose in an effort for future contributors to have an easier time grasping what your code is doing. Little syntax tricks like that can be neat, but often fall flat in well maintained project environments with C.
THIS. this is the video that FINALLY made it click for me. thank you Dave
Absolutely fascinating video!
Very helpful video, thank you!
Thank you for such a clear explanation
I have a project coming up for implementing data types so this really helps
Master Pointers! I've been waiting for him!
Love this, thanks Dave!
Excellent!
I am coming to C++ and Rust from other linguages both compiled/assembled (primary) or interperted. (50+ years in programming -- livelyhood/ hobby to retired and just hobby).
If this is a topic that should be explained:
o Coding: Best Practices, with emphasis on:
- Readability via Logical Format (after or along with the comments to explain)
- Preventing Memory Leaks
> Tools Available To Check - if such a thing exists
Links to, if this is something best explained by examining what you consider good coding practices.
Programming helps keep my mind sharp. Plus I just love it. When working I got paid for what I would have done for free (well almost). Looked up and it was time to go home. Couldn't wait to get back to where I left off.
Thanks again,
very good explanation. especially the function pointer part.
That was so good and so well explained 👏❤
Picked up writing some code for microcontrollers, my C is a bit rusty so these video's are very welcome.
I learnt about pointers in high school. Having programmed in a higher level language for the next decade or so I really never needed them except for knowing they’re really what's used under the hood for all the syntactic sugar I grew accustomed to. What clicked for me was when, trained to use polymorphism I tried to obtain the same result in c++ embedded only to realize you cannot send daya structes of different sizes to same function. Using pointers was the solution for passing different implementations of an interface of varying byte sizes.
This is actually pretty good. Until recently I had also been learning C and while it takes quite a bit longer to become proficient in it than I have, this talk about many pitfalls in that many beginners in that language fall into. While it's not the most convenient language to learn, it's still really useful in giving you an idea about how certain parts of computers work and hopefully let you learn higher level languages as well. I tend to agree that a bottom up learning pattern is better than bottom down, so even if you're not too interested in C, it's still a useful language to know, at least generally, even if you're not proficient in it. A lot of things in Programming are still based on it and it would just be weird if a proper programmer didn't know certain basic things about programming that you learn in C, even if you don't directly need it these days.
Keep ad it, I struggled at first too but once you get the hang of it, you'll wonder how you ever had troubles with it. If you're into it, programming can be a great thing, especially for people that like more practical uses of math but also many people in general. It's not nearly as rigid and a lot more creative than many like to think. So even if someone isn't that much into math, it can still be pretty nice to learn and use. Solving some of those problems you'll end up encountering, requires often a lot more than just purely logical, mathematical thinking, even if tends to be the basis of it. There's lots of creativitiy to be found in programming.
5:41 The -> pointer "dereference operator" is the shorthand variant for (*struct_name).member e.g. (*pHouse).SquareFeet
11:00 Usually when we program in C without classes ,we are using malloc. In C with classes (C++) we use new. Syntactically are both correct but new is safer.
2:58 Hardware registers or memory locations (physical memory locations on a CPU without MPU/MMU) can be accessed using a single line of code like *(byte *)53281 = 0x00;
"Usually when we program in C without classes ,we are using malloc"
It depends on the platform and application: in embedded microcontroller applications, which are typically memory constrained. would fail catastrophically in the event of failure, so malloc is rarely used in production hardware. As a result, memory and objects are typically allocated statically, or on the stack (typically small objects only on the stack).
Calling C++ “C with Classes” is sort of like calling Firefox “Netscape Navigator”. Or maybe like calling Windows “MS-DOS 1.0”.
@@danielrhouck It is something common among C (ansi, K&R, 90, etc) fans.
@@JohnDoe-kh3hy Classes are one of the *many* things C++ does differently than C, and they are *not* the most important one to this discussion.
@@danielrhouckNot really. Stroustrup referred to C++ as "C with classes". If it's good enough for him, it's good enough for me. It's a nice succinct way to describe the language conceptually.
There's an audio book coming? Wow! Can't wait! Have the physical book and love it so far, but finding time and mood for sitting down to read on paper is hard.
On the first example, it is important to note the memory address needs to be casted to a byte pointer. When I was learning, this confused me a bit, especially when working with custom types. You can have an entire buffer filled with data which looks random, but if you cast it to the correct type when dereferencing, all values in the custom structure are magically decoded, and it is extremely fast!
You're right, I remember "struct IntuitionBase * pIntuitionBase = (struct IntuitionBase *) LoadLibrary(:...)" is what threw me the first time!
@@DavesGarage We really needed the modern version of the auto keyword back on the Amiga. 80 columns only go so far.
Because i guess you did not start with assembly langauge. This was my 2nd language after Basic .... like all teenagers in the early 1980s home computer time. Feeling sad for the current generation that think it's not only magic but black magic.
@@llothar68 actually, in my Electrical Engineering curriculum in 1999 I took a class in ANSI C in Unix and an Assembly class. In the Assembly class I wrote a 8088 CPU emulator, which was both frustrating and fun! I ended up using assembly programming PIC microcontrollers more than anything else. I used the term “magic” because I know what it is doing under the hood for me, and how much effort the C language saves us rather than writing in pure assembly! Cheers! Edit: it was the 8080, not the 8088-long time ago and I have lost the floppy disk where I had a backup. Oh well…. My degree is in Electrical and Computer Engineering (ECE) and I took quite a bit of digital design classes, focusing more on hardware than software.
@@llothar68 im self taugh software engineer, i did not went to cs, and I know this stuff, cause I love digging deep, no need to feel sorry. most of these jobs doesnt require this knowledge, yo ucan still learn it as hobby
Free the mallocs!
Awesome video. Pointers are always misunderstood and often not done properly, they get especially finicky when you start using classes and C++ conventions, like the Trilogy of Evil (Copy, Assignment, Destructor operators) where data inside pointers has to be handled, not just the pointers themselves. One thing I came across was that in classes, you can allocate memory space with malloc, but it will not call the constructor for you. Another thing I've come across a lot when debugging is that people will call delete on the pointer when it's freed, but you also have to set the pointer to null in order to not leak that last bit of memory.
One thing that needs to be taught is how to clean up after your allocations (free() and delete/delete[]). I never learned this from three separate classes, until I went for a Game Development degree at Full Sail.
Thanks for the pointers.
This is very helpful. Thank you!
Thanks Dave, helpful stuff
👍👍Thanks Dave!
great video; keep them coming
Thanks for this, I always had pointers as something nasty but this video helped me. :D
Nice one. I found this video easy to grasp
I understood the point of pointers when I tried to access registers in a microcontroller. And to this day it makes the most sense of using them.
I love these C episodes!
Feels like a PBS documentary. love it.
great explanation mr. dave
Dave, I've been watching your channel for a while now, you might not read this, but I found this video very interesting. I started to learn to code several years ago, and got stuck in tutorial hell in several language. C is the first one after many years I've actually stuck with. I guess my brain is wired different, so the features of a lot of the new languages have too much abstraction for me. I like to know how things actually work, and C has been a huge stepping stone for me to finally get into software engineering. It's been more of a hobby for me, but I would like to do something involved in it whenever I retire from the military God willing. I understand hardware very well from my background of troubleshooting, and working on weapon systems that employed digital electronics, radar theory, signal data conversion etc, but programming was always a mystery for me, it sounds stupid I guess, if I can grasp hardware, software should be easy. Thankfully C exists. My question to someone with your background, is there a good method of connecting with people other than reddit, that could help with pointing to resources to expand my knowledge on C and the data structures/algorithms that are needed to be learned in the industry?
6 years of college working in C++ and i had never even heard about function pointers, thanks for showing me something i didn't even think was possible!
Function pointers are kindof the origin of object oriented programming. You would create a struct with function pointers as member variables. Then a "constructor-like" function could initialize the struct with the desired functions and voilá you have a class. C++ started out as a transpiler to C and, I might be wrong on this part, that is how i think it translated c++ classes into c structs.
Function pointers are currently almost not used (directly) in modern c++ (of course they exist and can be used if needed): most of the functionality was moved into lamba/function objects which is more robust and powerful solution (with some small problems). Also operators new/delete should not be directly used (as smart pointers are better option with make_shared and make_unique templates).
The Commodore 64 screen background colour byte example was brilliant!
Liked the parts where you shared why we would want to use pointers. Like the malloc api context was good to learn about.
Also too, (kept in my mind) the stack on 6502 is so small you could never pass a struct like item to a function with anything but a pointer.
I got my first taste of this type of pointer use (outside of assembly language) when I had to learn Modula-2. Thankfully it was a realtively small leap from there to using them effectively in C but the pointer declaration and use nomenclature in C was a bit confusing. This was very helpful thanks.
Online course sellers hatehim! Man shows up, explains the important things and crashes a whole 15$ course industry!!!! Actually I never understood half the things you talked about because I was reading about them on stackO or those CS50 notes. Thanks a lot!
Great topic, thanks 👍
this video deserves more views!
Once the light bulb went on in my head, it was mind-blowing. I was obsessed with it for months afterward.
Even though I come from TTL and then Assembly, I’ve always had inordinate amounts of trouble with symbology involving assembler-directives, figuring out other peoples UIs and pointer notation. 😢
Maybe I’ve been living on the ‘Spectrum’ all along 😂
Thanks for the video and clearing up some of the confusion with the notation! 😊
This was good for me thank you Dave
The very first programming language I learned, back in 1995 when I was 11 years old, was C. I had to tackle pointers from the get go, and of course they were a difficult topic for a child to grasp initially. But it made a HUGE difference for me when, years later, I started learning more high level languages such as Java, C#, and Ruby. I was WAY ahead of my colleagues who were learning those as their first programming languages, as the internals of what we were doing were much more intuitive for me.
I hit "thumbs up" on the video for the thumbnail alone, lol.
Legendary explanation.
Damn for some reason I couldn’t pick this up in university but the way you’re explaining it finally makes sense lol.
Thank you this really helps me get started with C++ ❤
I once had to create an array of function pointers. I remember nearly going blind with the syntactic gynastics that was required to create the thing and actually use it without leading to memory leaks. That was some 30 years ago, when I was programming embedded systems. Anyways, I strongly agree that mastering pointer syntax is important to improve your code READING skill. Oh, yah, and I heavily commented all that code. I typcially had more comments in my code then code, but I recall going way overboard commenting that code.
I made the jump to C from Assembly, somewhere in the eighties.
Pointers are trivially easy to understand if you know assembly.
I love function pointers. I thought that was the coolest shit when I was studying CS in college.
Very good tutorial which needs to be reminded now and then and again :D
Glad it was helpful!
[C]lear and straight to the point(er). 🎯
Thank you so much sir for this, it means a lot for a beginner like me 🙏. I am a Java/Kotlin programmer, (I know c/c++ but only the basics) I have wanted to master C++ for a long time, and now I think I can😅,
Thanks again 🙏
❤ From India 🇮🇳
BYOB - Bring Your Own Bytes?
We who are about to design and build salute you!
Beautiful video I enjoyed it a lot
Excellent tutorial