@@PaulProgramming Until today I have learned that c++ has true pass by reference, I always think java and c pass by pointer value is the same as pass by reference!
finally someone has explained this, it was really confusing to study this and everyone was explaining the difference between reference and value, took me a while to find the subject i was looking for
that's true, I've learned today that unlike pointer, reference variable doesn't occupy memory space, which is very shocking stackoverflow.com/questions/1179937/how-does-a-c-reference-look-memory-wise/38310081
You really have a knack for teaching, you made me understand pointers in 12 minutes more than I did the first week I learned it. Thanks man, you're brilliant.
Summary: Passing in a pointer by copy/value means that you "clone" the pointer of interest, and you will not be able to change what the original pointer is pointing to (certainly you can change values of what it is pointing to...but not the pointer itself...). If you pass by pointer reference (physically passing in the pointer itself), then you may change what the pointer is pointing to. Hope this helps.
@Jay Jay To avoid making a copy. Useful for deletion, to avoid having a dangling pointer, or a pointer pointing to some undefined junk (assuming you pass a pointer by copy and call delete on what it is pointing to), and that object is dynamically allocated of course. After calling delete on a pointer, for best practices you should set that pointer to be equal to nullptr. This is of course only useful if the pointer can still be accessed at a later time (was passed by copy and not by reference) in the execution of the program, but if that is not the case, then setting the pointer to nullptr is unnecessary. Passing a pointer by reference should be used judiciously, really only when you are going to be calling delete on an object allocated on the heap that the pointer is pointing to. If you don’t call delete and assign the pointer to some other object (stack or dynamically allocated, doesn’t matter), then you will suffer a memory leak if the object that the pointer was originally pointing to was dynamically allocated (on the heap). You can avoid having the responsibility to call delete by using smart pointers in modern C++ (C++11 and later standards).
Hey Paul. This is the first video of yours that i have watched and i absolutely loved it. This is absolutely the way how programming concepts must be taught. A big ❤️
You did a great job of explaining this. I read a C++ book several years ago, and I got pointers and references, but when it got into references to pointers, pointers to references, references to pointers of references, etc., my eyes glazed over. It all went completely over my head. Since then, when I encountered this, I would just skip it. However, this explained it so well. Thank you!
This upload was suggested in my home feed yesterday evening. I saved it in my watch list and after watching, Subscribed for more like this. It was probably suggested bc I was searching for info about pointers a few days ago. ...Still I like to share the hidden metrics behind how I came across a channel when I subscribe. Most CC's go through their upload metrics but it's hard to assess the figures independently ;) I'm Jake BTW, an electronics hobbyist. I don't care if you check out what I do. I'm not monetized nor do I plan to be. My playlists are a form of personal notes on electronics. This upload has been added to my "Programming C" playlist. All of my playlists (and subscriptions) are listed publicly for others that might find a compilation of references indexed by subject helpful. I only add what I watch, find helpful, and want to save a reference to. This upload helped me understand pointers a little better, but my initial curiosity from a few days ago is still unanswered. When it comes to hardware on a microcontroller, how does a pointer work with an input/output pin? For example, if an interrupt happens once, a function is called that sets pointers A, B, and C, to pins 1, 2, and 3 to check boolean input state. Then it does a bunch of magic. If the interrupt happens again pointers A, B, and C are set to pins 4, 5, and 6, and...magic etc. At the end of the magic function the outcome is an action using a pointer to an output pin. If that made any sense... my main problem, I guess is, what is an address in relation to a hardware I/O. If I create a pointer to an I/O does that copy the current state of the I/O into a memory location, or is an I/O pin simply another address like any other? Anyways...you don't need to answer that. It's just something to think about. I haven't found a solid answer to that one yet while searching for info about pointers. I'm probably asking the wrong questions but if I'm looking for this info perhaps others are as well, and if content were made to address it others would find it helpful ;) -Jake
For the confused, here's more of an explanation using the code he used in the program (Note: it helps if you have a clearer grasp of pass by value and by pass by reference): I want to start out by saying, and I wish he clarified this in the video, that he initialized gptr as a global variable and that is why he is able to access and use it in the functions. Pass by Pointer: You begin by passing an int pointer variable into passByPtr because the argument that the function accepts is that type. Let's pass int* p into the function. So that looks like: passByPtr(p); The function, passByPtr(int * ptr), creates a new object. The new object is ptr. And the contents of p is copied into ptr. P AND PTR ARE SEPERATE OBJECTS. However, they have access to the same memory address. The advantage of this is you could dereference ptr and it would change the contents of p. But if you change the memory address of ptr, there would no difference. So in the function if you did this: *ptr = 43; // you dereference by using the * operator in front of the variable // when you dereference a pointer, you access the value at that memory address A pointer is just a variable that holds a memory address so you are just creating a new object with the same memory address. When the function ends, ptr goes out of scope and wiped off the top of the stack. Pass by Pointer Reference: You begin the same as you would by passing a pointer. Let's pass p into passByPtrRef(int * & ptrRef). The difference now is that in passByPtrRef(int * & ptrRef) , the function DOES NOT create a new object. ptrRef and p are the same object. ptrRef is just an alias to p. Any changes made to ptrRef will be applied to p.
Man these videos are amazing. Some people might find that you went a bit too fast on this one but I saw the video on the difference between passing by value, passing by reference and passing by pointer, just before this one, and this all felt like a very natural 2nd part, with no need to re-write the code from scratch, as you did in that other video. Maybe you should label them as part 1 & part 2 so people don't get lost. Anyway great video, I was getting those concepts confused. Thanks Paul.
😮I... I'm in awe of how beautiful this explanation was. It's a work of art. Masterful. Just a few minutes into it I had to like and subscribe. This is truly an amazing gift you've given everyone. I'm eternally grateful. Thank you for this video.
So a pointer reference is like a reference (a reference is like creating an alias/nickname of a variable/identifier). A pointer reference is like creating an alias or nickname of the pointer (a pointer is creating a memory address that points to whatever it points to).
Awesome video! Could you do a video on double pointers? I really like your teaching style. EDIT: Also, what is the different between using this rather than using a double pointer?
can you please make more videos on specifically: queues, graphs & graph traversals, tries, sorting algorithms(merge sort, quick sort, insert sort, heap sort, etc), and big-o notation?
This is how my understanding of why Java is pass by value. If you pass a reference to a method in Java, that method receives a copy of the reference, a copy of the memory address, while in C++ you have the pass by reference option where your function or method can actually manipulate the variable that you have passed as an argument instead of getting a copy of that variable. P.S. Please indent the code.
Hey 1 quick question, whats the difference between pointer to pointer and pointer reference? both of it seems to did the same thing by manipulate the address of pointer pointing to and the data of the pointer is pointing to
Thanks a lot for great explanation.. one silly question.. a call by reference function signature is like that: void foo(int& x).. considering this, should passbyrefptr be like that: void passbyrefptr (int& * ptr).. because former says reference to a integer variable and the latter ,i think, should say reference to a int pointer.. i confuse the syntax a lot
@Paul Programming , dude please make a video of pass by pointer but with functions with a dynamic 2D array , ill be very happy if you make 1 little video , nice video though, keep up :)
I really like the way you teach. It's concise, it's visual and you explain it so anyone can can understand it. Thank you! -just a fan
+Sheheryar Wasti I'm glad you like it
but why you stopped :/ ...
Agreed. Even myself with no experience with c++ could follow along like a breeze.
@@PaulProgramming Until today I have learned that c++ has true pass by reference, I always think java and c pass by pointer value is the same as pass by reference!
@@PaulProgramming GOD U R a GREAT TEACHER :) thank U again
finally someone has explained this, it was really confusing to study this and everyone was explaining the difference between reference and value, took me a while to find the subject i was looking for
that's true, I've learned today that unlike pointer, reference variable doesn't occupy memory space, which is very shocking stackoverflow.com/questions/1179937/how-does-a-c-reference-look-memory-wise/38310081
There are NO bad STUDENTS ONLY BAD TEACHERS !!! Thank u again it worked
You really have a knack for teaching, you made me understand pointers in 12 minutes more than I did the first week I learned it. Thanks man, you're brilliant.
Best coding channel i've found yet. Will definitely be using it for the remainder of my coding course.
Summary: Passing in a pointer by copy/value means that you "clone" the pointer of interest, and you will not be able to change what the original pointer is pointing to (certainly you can change values of what it is pointing to...but not the pointer itself...). If you pass by pointer reference (physically passing in the pointer itself), then you may change what the pointer is pointing to. Hope this helps.
Mo Aboulmagd Thank you for this, your summery really helped understand this topic and the video better.
@Jay Jay To avoid making a copy. Useful for deletion, to avoid having a dangling pointer, or a pointer pointing to some undefined junk (assuming you pass a pointer by copy and call delete on what it is pointing to), and that object is dynamically allocated of course. After calling delete on a pointer, for best practices you should set that pointer to be equal to nullptr. This is of course only useful if the pointer can still be accessed at a later time (was passed by copy and not by reference) in the execution of the program, but if that is not the case, then setting the pointer to nullptr is unnecessary.
Passing a pointer by reference should be used judiciously, really only when you are going to be calling delete on an object allocated on the heap that the pointer is pointing to. If you don’t call delete and assign the pointer to some other object (stack or dynamically allocated, doesn’t matter), then you will suffer a memory leak if the object that the pointer was originally pointing to was dynamically allocated (on the heap). You can avoid having the responsibility to call delete by using smart pointers in modern C++ (C++11 and later standards).
Hey Paul. This is the first video of yours that i have watched and i absolutely loved it. This is absolutely the way how programming concepts must be taught. A big ❤️
One of the best lesson I found on internet, very clear and complete, compliments.
I like your teaching style with bunch of visualisation. The best explanation that I've ever seen, thank you for your work!
A simple explanation and yet better and more concise than many other explanations. Thank you
You did a great job of explaining this. I read a C++ book several years ago, and I got pointers and references, but when it got into references to pointers, pointers to references, references to pointers of references, etc., my eyes glazed over. It all went completely over my head. Since then, when I encountered this, I would just skip it. However, this explained it so well. Thank you!
I just have seen 2 videos of your tutorial and subscribed immediately. Super clear, concise explanation. Keep teaching.
Outstanding explanation! Thank you!
This upload was suggested in my home feed yesterday evening. I saved it in my watch list and after watching, Subscribed for more like this. It was probably suggested bc I was searching for info about pointers a few days ago. ...Still I like to share the hidden metrics behind how I came across a channel when I subscribe. Most CC's go through their upload metrics but it's hard to assess the figures independently ;)
I'm Jake BTW, an electronics hobbyist. I don't care if you check out what I do. I'm not monetized nor do I plan to be. My playlists are a form of personal notes on electronics. This upload has been added to my "Programming C" playlist. All of my playlists (and subscriptions) are listed publicly for others that might find a compilation of references indexed by subject helpful. I only add what I watch, find helpful, and want to save a reference to.
This upload helped me understand pointers a little better, but my initial curiosity from a few days ago is still unanswered. When it comes to hardware on a microcontroller, how does a pointer work with an input/output pin?
For example, if an interrupt happens once, a function is called that sets pointers A, B, and C, to pins 1, 2, and 3 to check boolean input state. Then it does a bunch of magic. If the interrupt happens again pointers A, B, and C are set to pins 4, 5, and 6, and...magic etc.
At the end of the magic function the outcome is an action using a pointer to an output pin.
If that made any sense... my main problem, I guess is, what is an address in relation to a hardware I/O. If I create a pointer to an I/O does that copy the current state of the I/O into a memory location, or is an I/O pin simply another address like any other?
Anyways...you don't need to answer that. It's just something to think about. I haven't found a solid answer to that one yet while searching for info about pointers. I'm probably asking the wrong questions but if I'm looking for this info perhaps others are as well, and if content were made to address it others would find it helpful ;)
-Jake
For the confused, here's more of an explanation using the code he used in the program (Note: it helps if you have a clearer grasp of pass by value and by pass by reference):
I want to start out by saying, and I wish he clarified this in the video, that he initialized gptr as a global variable and that is why he is able to access and use it in the functions.
Pass by Pointer:
You begin by passing an int pointer variable into passByPtr because the argument that the function accepts is that type. Let's pass int* p into the function. So that looks like:
passByPtr(p);
The function, passByPtr(int * ptr), creates a new object. The new object is ptr. And the contents of p is copied into ptr. P AND PTR ARE SEPERATE OBJECTS. However, they have access to the same memory address. The advantage of this is you could dereference ptr and it would change the contents of p. But if you change the memory address of ptr, there would no difference. So in the function if you did this:
*ptr = 43; // you dereference by using the * operator in front of the variable
// when you dereference a pointer, you access the value at that memory address
A pointer is just a variable that holds a memory address so you are just creating a new object with the same memory address. When the function ends, ptr goes out of scope and wiped off the top of the stack.
Pass by Pointer Reference:
You begin the same as you would by passing a pointer. Let's pass p into passByPtrRef(int * & ptrRef). The difference now is that in passByPtrRef(int * & ptrRef) , the function DOES NOT create a new object. ptrRef and p are the same object. ptrRef is just an alias to p. Any changes made to ptrRef will be applied to p.
But if the parameter is just (int &ptref) what difference would it make?
a clear explanation and visualization for a complex subject. Well done and thank you!
Man these videos are amazing. Some people might find that you went a bit too fast on this one but I saw the video on the difference between passing by value, passing by reference and passing by pointer, just before this one, and this all felt like a very natural 2nd part, with no need to re-write the code from scratch, as you did in that other video. Maybe you should label them as part 1 & part 2 so people don't get lost. Anyway great video, I was getting those concepts confused. Thanks Paul.
That illustration has helped me a lot to understand the concept. Thank you so much.
i really like your tutorial. It's very simple very basic. I didn't find anything better than this tutorial even in Udemy.Thanks !!!
😮I... I'm in awe of how beautiful this explanation was. It's a work of art. Masterful. Just a few minutes into it I had to like and subscribe. This is truly an amazing gift you've given everyone. I'm eternally grateful. Thank you for this video.
Thank God, I finally found the video I'm looking for, God bless you bro, you save my stress
Thanks for the tutorial Paul. This video was extremely helpful and I think I understand it a lot more now.
This video and your other video, it explained pointers and references way better than other sources.
WOW. I will be coming back to this video several times and recommending it to my friends. Thank you.
one of the best teachers!
So a pointer reference is like a reference (a reference is like creating an alias/nickname of a variable/identifier). A pointer reference is like creating an alias or nickname of the pointer (a pointer is creating a memory address that points to whatever it points to).
great concept ❤
I have been searched this type of video for 5 days... You just make me cry 😭 dude
Best explanation of this subject. Thanks
Like the way you visualize lession, respect (y)
Very good. We just need the right person to explain. Thanks !!!
It was a really wonderful explanation, Thank you Paul!!
Best explanation of pointers in C in my opiniok. Thank you
Thank you ! Excellent tutorials.
love you graph !
Great and clear explanation! Thank you very much!
Terrific explanation.
This was a REALLY helpful video. Thank you Paul.
Amazing lesson, thank you!
Underrated video! Needs more views ;)
Fantastic tutorial, helped me a lot with understanding pointers. Thank you
Awesome videos man,very helpful,thank you.
You have a very lucid style of explanation! You earned a new subscriber Sir.
Great lesson, this one and others, so clear! Thank you.
Congratulations from Brazil.
Thank you so much. Your explanation was very nice. It helped me a lot.
visuals are extremely helpful thank you
Great!!!! Excellent explanation and concept cleared... Thank you....
really really thank you guy! clear and impressive. that's really helps me
really good tutorial about a confusing topic :D helped a lot
Great explanation, thanks !
This is so helpful! Thanks!
i like the breakdown of steps
Very clear! I like this video
Very helpful video. Thank you!
great lesson , i really understand and enjoy it . thank u so much !
Thanks. This was very helpful!!!
This is an excellent video.
Very interesting. Thank you very much.
thanks a lot man! was stuck on this one, cleared all my doubts
11:50 my brain starts to overclock... good explanation, I have to watch the last 30 seconds 3 times in slow mo to get it... LOL
same bro
Awesome video! Could you do a video on double pointers? I really like your teaching style.
EDIT: Also, what is the different between using this rather than using a double pointer?
awesome explanation!!! thanks dude
amazing visualization
Thank you, great video.
Thanks you, well explained!
Great stuff!
Thanks!
can you please make more videos on specifically: queues, graphs & graph traversals, tries, sorting algorithms(merge sort, quick sort, insert sort, heap sort, etc), and big-o notation?
Nice explanation
gooood before my exam good content thumbs up
this is a great video, new sub
Paul you are my man finally i understand pointer and the fucking reference
This is how my understanding of why Java is pass by value. If you pass a reference to a method in Java, that method receives a copy of the reference, a copy of the memory address, while in C++ you have the pass by reference option where your function or method can actually manipulate the variable that you have passed as an argument instead of getting a copy of that variable.
P.S. Please indent the code.
U R A GOD :) thk U
Good lecture
Bless you.
Awesome video
Thank you!!
thank you
Very Helpfull :)
Excellent
very clear
SUPER video
Good video
Great video Paul!
Will you make a tutorial about smart pointers too?
Thank you sir ! that's really helpful
Is there a video in your channel talk about the *_heap_* and when should I use the *_new_* keyword ?!
I love it
Hey 1 quick question, whats the difference between pointer to pointer and pointer reference? both of it seems to did the same thing by manipulate the address of pointer pointing to and the data of the pointer is pointing to
Nice vid
AMAZING
is this different for objects? my own struct for instance
Excellent.in 2020
Sweet!
what text editor do you use?
My man.
Thank yoouuuu
Oh yeah thanks sir
Thanks a lot for great explanation.. one silly question.. a call by reference function signature is like that: void foo(int& x).. considering this, should passbyrefptr be like that: void passbyrefptr (int& * ptr).. because former says reference to a integer variable and the latter ,i think, should say reference to a int pointer.. i confuse the syntax a lot
omg.. great
@Paul Programming , dude please make a video of pass by pointer but with functions with a dynamic 2D array , ill be very happy if you make 1 little video , nice video though, keep up :)
put at 1.5x speeed. The explanation and the pronunciation are easy to understand. I d like to know which tools are being used to produce the drawings.