Just like professor Feynman said if you understand something well enough you’ll be able to explain it in the most simplest way.and that’s exactly you’ve done. Thank you for making this difficult topic understandable!!!
I went in with no expectation, I finished with complete understanding of what I should be doing, and also a slightly better idea on pointers/array. Thanks a bunch, appreciate your work greatly.
This has been the most easy -to-understand tutorial ever since. Thanks a lot. Just a little something : on function free2dIntArray() we shouldn't include the third parameter dim2 on the function's prototype.
Nice explanation! However there's an optimized way to allocate a 2d array int **p = (int **)malloc(rows * sizeof(int *)); p[0] = (int *)malloc(rows* columns * sizeof(int)); for (i = 1; i < rows; i++) { p[i] = p[i - 1] + columns; } free(p[0]); free(p); In this case, a single block of memory is allocated and rearrange the pointers to form an array. This is computationally better for a few reasons: 1. The allocation engine does not perform as many allocations as before. 2. As opposed to the conventional implementation, there's no extra bytes between rows to keep count of the memory blocks. That means the final 2d array is represented in a continuous memory block. Therefore, there's no need to make large moves between those positions in the memory. 3. free() is called twice only. The conventional implementation depends on the 'rows' size.
I know I'm a bit late to the party but goddammit that explanation is so good. pleace don't stop doings vids like this you've made a difference in someone's life
Can you please make complete knowledge of c/cpp, You are way of teaching so good and you really get us into deep which really i want !! Thanks for this video 🤠
I finally understood why it works like that thanks to you :) Just got a question, in the freeing part (the correct one) wouldn't it be the same if I didn't pass dim2 as a parameter, since it's not needed for deallocating the memory?
Actually the true dynamic 2d array can be allocated with a pointer to array. Just do `int (*arr)[dim2] = calloc(dim1, sizeof *arr);`. And that's all. Just remember to call `free(arr)` at the end.
Thanks for commenting. If you are using fixed size strings you can simply substitute with throughout this video and it will work in the same way. In this case dim1 would be the number of strings and dim2 the maximum string length, including the end of string sentinel. If you want a jagged array (strings of different lengths), you’d need to do things a bit differently. Is the latter what you had in mind?
As you say, it is not contiguously allocated 2d array: each row will be allocated to separate locations on the heap. Also, I get what you mean by lookup table: the "column array" of pointers to integers are used to "look up" each row. I wouldn't personally call it a lookup table, though. For me they (lookup tables) are a higher order construct used for a smaller set of specific applications.
It would have been nicer if you give meaningful names to parameters like instead of Dim1 Dim2 you can could have written Row and col, in video you are mentioning them as row and col why not name them the same.
perfect. the only one that explained clearly so far.
Just like professor Feynman said if you understand something well enough you’ll be able to explain it in the most simplest way.and that’s exactly you’ve done. Thank you for making this difficult topic understandable!!!
Underrated video, you should be top search for c programming. It makes so much more sense to me now
Thanks!
To be honest, this is the most comprehensible explaination on youtube, thank you so much !
thank you man, you save me from my upcoming test, thanks a lot
thank you for the effort creating this wonderful video
Dude is a GOAT. As a grad student taking a CS class (non cs major) this has made it extremely clear how to allocate dynamic memory. Thanks!
please you are amazing , thnks a lot and you have made my difficulties become simple for me 💯🙏🙏
I went in with no expectation, I finished with complete understanding of what I should be doing, and also a slightly better idea on pointers/array. Thanks a bunch, appreciate your work greatly.
Wow ! Great explanation, i'm french and your english is very understandable ! Thanks a lot !
Excellent explanation
Best video on this topic !! Thanks alot.
Finally some good explanation about 2D dynami array! Piece of gem! Thank you!
Very informative 🔥
Great video to help shake out the cobwebs. My favorite on RUclips for the topic.
Thank you!
This has been the most easy -to-understand tutorial ever since. Thanks a lot.
Just a little something : on function free2dIntArray() we shouldn't include the third parameter dim2 on the function's prototype.
Thanks for your kind words and yes you are correct.
Very good explanation sir it's a superb video. Everyone can understand this concept without any doubt.
Very well explained , I'm glad I found your channel !
Thank you so much for the explanation!!
Nice explanation! However there's an optimized way to allocate a 2d array
int **p = (int **)malloc(rows * sizeof(int *));
p[0] = (int *)malloc(rows* columns * sizeof(int));
for (i = 1; i < rows; i++) {
p[i] = p[i - 1] + columns;
}
free(p[0]);
free(p);
In this case, a single block of memory is allocated and rearrange the pointers to form an array. This is computationally better for a few reasons:
1. The allocation engine does not perform as many allocations as before.
2. As opposed to the conventional implementation, there's no extra bytes between rows to keep count of the memory blocks. That means the final 2d array is represented in a continuous memory block. Therefore, there's no need to make large moves between those positions in the memory.
3. free() is called twice only. The conventional implementation depends on the 'rows' size.
This is a life saver. Thank you!
Thank you, this was an approachable explanation that helped me finally understand the concepts.
I know I'm a bit late to the party but goddammit that explanation is so good. pleace don't stop doings vids like this you've made a difference in someone's life
Amazing explanation way more clear than my college professors
best explanation , keep it going !
man thank you so much this video I find it the best one on RUclips ♥
I feel like I don't need to know this for the problem set I'm doing, but this was very helpful regardless. Thank you!
exactly what I needed :) I'm working on a small project that solves a system of user input equations and this is the core of it
Thank you so much man! This was great.
amazing explanation!! Thanks alot really
Clearly understood! Thank you sir.🙇
Thank you very much for this wonderful content.
this video is so good!Thanks!
You're the best
thanks bro!
great video
Thanks!
This was gem
TE AMO GRACIAS !!!
B E A U T I F U L EXPLANATION
This was a great video!
Thanks for taking the trouble to comment - appreciated.
thanks a lot that was quite helpful.
perfect video
Can you please make complete knowledge of c/cpp, You are way of teaching so good and you really get us into deep which really i want !!
Thanks for this video 🤠
Thanks for your kind words Zuned. I'll try and upload some other material soon.
@@jatinthebox8574 willwait for more.
thank you sir!
you're a fuckin lifesaver, man
thank you sir.
i love this
I finally understood why it works like that thanks to you :)
Just got a question, in the freeing part (the correct one) wouldn't it be the same if I didn't pass dim2 as a parameter, since it's not needed for deallocating the memory?
Yep, you are right. Well spotted.
legend
I hate c keeps telling there is a leak and when i try to free that memory thats leaking i got an invalid free
this is the one
why is (int**) debatable? is there something wrong with using it? thanks!
You just do not need it, but I think it makes the code more readable. I think it reminds people of Java, which they do not like, but I do 🙂
make more videos please
Actually the true dynamic 2d array can be allocated with a pointer to array. Just do `int (*arr)[dim2] = calloc(dim1, sizeof *arr);`. And that's all. Just remember to call `free(arr)` at the end.
That's a really neat way of doing it. Do a video to explain how it works ? ;-)
@@jatinthebox8574 sure sir
Can you please make a video about dynamic allocation for array of strings please
Thanks for commenting. If you are using fixed size strings you can simply substitute with throughout this video and it will work in the same way. In this case dim1 would be the number of strings and dim2 the maximum string length, including the end of string sentinel. If you want a jagged array (strings of different lengths), you’d need to do things a bit differently. Is the latter what you had in mind?
why did u stop posting ? 😥
Just wasn't much interest 😔
Strictly speaking isn't this a lookup table not a true contiguously allocated 2d array?
As you say, it is not contiguously allocated 2d array: each row will be allocated to separate locations on the heap. Also, I get what you mean by lookup table: the "column array" of pointers to integers are used to "look up" each row. I wouldn't personally call it a lookup table, though. For me they (lookup tables) are a higher order construct used for a smaller set of specific applications.
It would have been nicer if you give meaningful names to parameters like instead of Dim1 Dim2 you can could have written Row and col, in video you are mentioning them as row and col why not name them the same.