struct Basics | C Programming Tutorial
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- เผยแพร่เมื่อ 8 ก.ค. 2021
- An overview of struct in C. Source code: github.com/portfoliocourses/c.... Check out www.portfoliocourses.com to build a portfolio that will impress employers!
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Also note in this video when we assign y to x, this would *also* be a memory leak, which is bad! 🙂 I was trying to stay focused on structs in this video, but this other video covers memory leaks which are important to avoid: th-cam.com/video/lQCLAKfcYI4/w-d-xo.html.
This channel is awfully underrated. Respect.
Thank you so much for the kind feedback, I really appreciate that. :-)
frfr
There can't be a better video on structs other than this one on youtube. Pretty much everything covered in one video.
Thank you for the positive feedback Daishak, I'm glad to hear you enjoyed the video! :-)
this is the best c tutorial in entire youtube, i have been searching for months and now got the best content for c, thank you so much man
Structures confused the hell out of me when I started reading about them;
this video made them much more clear.
This is perfect. Thank you. Pretty much everything you need to know about structs all in one easy to understand video.
You’re welcome! Thanks for sharing that you enjoyed it, that’s excellent to hear! :-)
Very clear explanation about how pointers contain a reference to some area in memory and not the content of that memory area itself and why you need to be extra careful when reasigning pointers. Thank you so much for your work!
Once again an EXCELLENT tutorial!
You really make me love C, honestly.
Thank you very much for the positive feedback! :-) And I’m glad these videos are encouraging your own enthusiasm about C, I definitely love using it!
This channels quality content gonna be remembered for generations he teaches clear and concise thank you sir for your service to this populace
Thank you very much for sharing such positive feedback, that really motivates me to keep going with these videos! :-)
Omg thank you so much, this is so much better than two two hours lectures i had on structs...
I have an exam next week and gonna watch the other videos on pointers and strings if you have any❤❤❤
I know programming is difficult but he made it easy. Really appreciate this channel :)
I'm glad you thought the tutorial made it easy Tyron! :-) And thanks so much for the positive feedback, I appreciate it.
You have explained the topic of shallow copy operation very well.
Thank you! :-)
wow, struct fully explained. Thank you for helping me and others to understand what you r self strive for.
You’re very welcome Naboulsi, I’m glad the video helped you out! :-)
I've learned so much about C these last two/ three months thanks to you :)! Muito obrigado pelos seus vídeos!!!
I’m so glad to hear these videos are helping you out, thank you for sharing this! :-)
Wow! This video really blew me away. Great video to learn struct
I'm glad that you enjoyed it! 😀
Thank you, You did very good explanation with exampels. You finally made me learn to use structs properly and to pass them correctly to different functions.
You're welcome! :-) I'm really glad to hear that this video helped you to learn how to use structs!
You helped me a lot understanding struct. Thanks!
You’re very welcome Adam! :-)
This is by far the best video on struct, very good content.
I'm glad that you enjoyed it, and thank you for sharing this positive feedback! :-)
Thank you very much, please keep uploading videos. Much love!
You’re welcome, and I’ll definitely keep uploading videos! :-)
After you explained struct I was about to leave to find a video about typedef then you explained it. Great video!
I'm glad you liked it! :-)
Very clear and concise, thank you for this quality content.
You’re welcome Fadi! I’m glad to hear you enjoyed the video. :-)
@@PortfolioCourses hi sir I am having a doubt why we used strcpy to assign string to structure members of " name and ID " Instead OF ASSIGNING directly like normal structure variable of age and grades . I have tried to assign string to structure members of "name and ID " when I compiled my code I got an error .
why and what is the difference can you pls explain me ???😊
@@ramakrishna4092 We can initialize the string when we declare the struct using an initializer list as in this example: www.delftstack.com/howto/c/c-initialize-struct/. But if we first declare the struct, and then set the members with individual assignment statements, we cannot later use = to assign to the string.
It's like how in C we can initialize an array once with the {1,2,3,4,...} type syntax, when it is declared, but not afterwards.
When we make a char array we can initialize it once to a string literal when it is declared:
char string[] = "store this string";
But if we had this it would not work:
char string[20];
string = "store this string";
The same thing is happening here essentially, when we declare the struct the string is essentially declared and created similar to the above example. We cannot assign to it later with = "some string", we then need to use strcpy().
It's just how C works that it's like this really. 🙂
My teacher is totally useless. This channel is the only thing, keeping me from failing. Thank you so much, you have a knack for explaining hard material so a noob can understand it.
You’re very welcome, I’m really happy to hear you’re finding the channel helpful! :-)
The best explanation on struct ever!!
Thank you very much for the kind feedback, I’m glad you’re enjoyed it! :-)
thank you, the best content I have seen about this topic. Great! :)
You’re welcome Karolina, and thank you for the positive feedback! :-)
Thanks for this wonderful, clear and succint explanation
You're welcome Rahmat, I'm glad you enjoyed it! :-)
el mejor video explicando structs, gracias por hacer este video!
de nada! :-)
This is truely a detailed source
Thank you bro!!
You're very welcome! :-)
thank you for making it easy on us champ.
that thing i can only comment is it was so clear... thanks and good luck!!!!!
You’re welcome Itachi! I’m glad you found it clear. :-)
very detailed. Thank you. 💯💯
You're very welcome Nicholas! :-D
hammer on a nail. Simple short to the point.
you are my favourite teachher so far thank youuu
Wow, thank you so much, you're welcome! :-)
Excellent ..very good channel.
using this video to study for structs on my next exam and you made everything super clear holy crap
I’m glad the video made everything super clear, and good luck on your final exam! :-)
Thank you, Amazing work.
You’re welcome, and I’m glad you enjoyed it! :-)
thank you! very good explaining😄
You're welcome, I'm glad you enjoyed the explanation! 🙂
very helpful! thank you so much
You’re welcome! :-)
your channel is a gem
Thank you for the positive feedback Mohamed, I appreciate it! :-)
its crazy how such high quality material is hidden on the internet. your videos should have millions of views!
I’m glad you enjoy them! :-)
Hopefully your courses will help me get an A in my technician year. Good work
Best c tutorial ever
thank you for this great job
Nice tutorial.... Very helpful
Thank you for the kind feedback Shanjo! :-)
thanks for the video, and great presentation
You're welcome, I'm glad you enjoyed it! :-)
thremendous tutorial in c
fullplaylist is superb
sir ❤❤❤💖💖💖💖💖💖
I’m really happy to hear that you’re enjoying the tutorial and playlist! :-D
best tutorials you can find!
Thank you very much for the positive feedback Jonathan! :-)
@@PortfolioCourses always helping mate. thank you so much!
i have an assignment now with an array of struct to represent items in a shop (name, price, amount). they asked us to make a program with different functions so the user can add a product and buy a product from that shop and so the array has to be synchronized between all functions. I don't know how to make it happen because we didn't learn pointers yet.
@@Jonathan-mu5nx I have some videos on pointers and structs you might like:
Introduction To Pointers: th-cam.com/video/2GDiXG5RfNE/w-d-xo.html
Arrow Operator: th-cam.com/video/w5XM1N7hLgc/w-d-xo.html
Dynamically allocate an array of structs: th-cam.com/video/lq8tJS3g6tY/w-d-xo.html
Good luck! 🙂
awesome content
always my go to
I'm so glad to hear you're enjoying the content! :-)
Love your videos! Learned more in two weeks than 5 months of studying. I have one question tho: When calling the function (at around 9:10 in the video) I get the error: a parameter list without types is only allowed in a function definition; when I try to compile it. (the error for the function call in the main body)
The source code for the video is here, does using this help? github.com/portfoliocourses/c-example-code/blob/main/struct.c
@4:00 Hi Kevin, I have watched this before and would love to learn how to copy this struct from an Excel Spread Sheet, and Paste it and Save it to Excel Spread Sheet. I appreciate if you have the time to do a video on that. This makes a very useful tool for embedded design. Thanks a million, Kevin.
Is the Excel filed saved as a CSV file? That may be do-able. If it's not some kind of binary .xls format I'm not sure how. :-)
CSV file would do it, yes.
Thanks!
I wanted to ask something about the data struct and when you declared x = y.
That struct only has a pointer variable so when you did x = y you are assigning the pointer value of y to x right? That's why when modifying x.array[0] if you print both x.array[0] and y.array[0] they have the same value, so in that example as we assigned the x pointer variable to be the same as y we lost the pointer to the original array that x was pointing to right? It still exists in memory but we can't used it?
Yes, the block is still on the heap, but we lost the pointer. It is one way to produce a memory leak
Thx!
You’re welcome! :-)
Amazing
I'm glad you liked it! :-)
Thank you! this video made so many things clearer for me! Any chance you'll make SDL tutorials for C?
I don’t have plans to right now but maybe it’s something I can do one day. :-)
@@PortfolioCourses yeyy, thank you!
Génial !
Thanks! :-)
This is heaven 😍
I'm glad you enjoyed the video! :-)
謝謝！
WOW thank you very much for the super thanks!!! :-D
Your introduction is very elaborate and comprehensive 😁. But Kevin 40 is quite old for a student, isn't he? 🤣
He’s a mature student. :-)
I have seen alot of your videos and are helpful,
I have a little problem how would I get computer serial Number.
system("wmic get bios serialnumber>sn.txt");
And store it in an array of character and then print it on screen.?
I really need help with that.
Sir,can I know which compiler you use
I have a question. In the assignment of structures, does the addresses of the structures also gets copied? E.g., When we do p1 = p2, does p1 also contains the address of p2?
Great question! :-) No, p1 and p2 each have their own address at which a struct is stored. And when we do p1 = p2, a memcpy() will effectively happen where p2's contents are copied to p1. But p1 and p2 each still are in different memory addresses.
quick question, what happens to the previous malloc'ed memory region of x after pointing it to y? does it just float in memory to be reclaimed by the OS later?
It's a memory leak. :-) Which means the memory has been allocated, but is no longer accessible by our program. It also won't be "returned" to the OS until the program terminates. So we call it a memory leak because the memory is no longer available for our program, but it's also not being used in a useful way either.
which IDE do you use?
Can i know why you didn't use the typecasting with malloc in this case
Or at least recommend a video to me to understand ,and thanks ❤️❤️
Great video. I have a question. What's the difference between a struct and class? And when to use them. I know class is by default private but how to use these two terms properly.
I don’t think C has classes that’s C++ but I’m also confused on like why classes were a necessary change from C to C++ I’m pretty sure it has something to do with OOP but I’m not too sure
Just looked it up I guess classes have a deinitializer function that destroys instances of the class so I guess you can’t tell if the structs are getting destroyed
19:55 x = y, wouldn't that be a memory leak? since you lost the original pointer (location) with the data still being there.
Great channel with great explanations, thank you!
I just fiddled around with memory and leaks. I hope this is correct and may help someone.
#include
#include
typedef struct {
int *array;
} Data;
void print_array(const char *name, Data data) {
printf("Array %s
", name);
for (int i = 0; i < 2; i++) {
printf("%i: %d
", i, data.array[i]);
}
printf("
");
}
void separate_data() {
Data x;
x.array = (int *) malloc(sizeof(int) * 2);
x.array[0] = 1;
x.array[1] = 8;
print_array("x", x);
Data y;
y.array = (int *) malloc(sizeof(int) * 2);
y.array[0] = 9;
y.array[1] = 9;
print_array("y", y);
free(x.array);
free(y.array);
}
void same_data() {
Data x;
x.array = (int *) malloc(sizeof(int) * 2);
x.array[0] = 1;
x.array[1] = 8;
print_array("x", x);
Data y;
y.array = (int *) malloc(sizeof(int) * 2);
y.array[0] = 9;
y.array[1] = 9;
print_array("y", y);
// deallocate memory of x because pointer x will be moved to y
free(x.array);
x = y;
print_array("x=y", x);
free(y.array);
}
int main() {
separate_data();
same_data();
}
I'm learning C, i'm an amateur wannabe from python, can i take the structs as objects, and the variables declared from the structs as instances?, I feel them like that
Great question Jay! :-) And yes that’s correct, when we define a type of struct it’s a lot like defining a class in Python (in other words, a type of object). And when we declare variables of that struct type, those are a lot like object instances.
@@PortfolioCourses thanks boss, i was kinda Lost on this till i related structs with classes
You’re welcome! :-)
difference between structs and class is that in structs, functions are private and data members are public, while in class, it's opposite. However, C does not have any concept of objects, as we don't instantiate. In C, structures are mainly used for the purpose of grouping various information under one name.
@@lradhakrishnarao902
1:42 A forty years old student! I guess you never stop learning ;-)
Hahaha :-)
do we need to free() the x and y array somehow, since we use malloc() ?
i actually found a solution:
we need to free x.array before we make x=y assign, then at the very end we free y.array. I was trying to free both x and y array at the very end but there was still a leak, so hope it might help someone
check for leaks on Mac with: CK_FORK=no leaks --atExit -- ./a.out
#include
#include
#include
typedef struct {
int *array; // pointer to dynamically allocated array
} Data;
int main() {
// initialise two structures named x and y of type Data
Data x;
Data y;
// stores 5 int in dynamically allocated array
x.array = malloc(sizeof(int) * 5);
y.array = malloc(sizeof(int) * 5);
printf("
X's pointer: %p
", x.array);
printf("Y's pointer: %p
", y.array);
x.array[0] = 1;
x.array[1] = 2;
x.array[2] = 3;
x.array[3] = 4;
x.array[4] = 5;
printf("
////// x.array ///////////
");
for(int i = 0; i < 5; i++) {
printf("x.array[%d] = %d
", i, x.array[i]);
}
y.array[0] = 9;
y.array[1] = 9;
y.array[2] = 9;
y.array[3] = 9;
y.array[4] = 9;
// 'x' with it's pointer to the array it has been set to point to the same array that 'y' is pointing to
// so they point to the same array,
// cuz the STRUCTURE STORES A POINTER TO THE ARRAY THAT WE DYNAMICALLY ALLOCATE
free(x.array); // free up the allocation before we assign
x = y;
// here we see that they both now point to the same pointer for an array
printf("
X's pointer: %p
", x.array);
printf("Y's pointer: %p
", y.array);
printf("
////// x.array after assign to y ///////////
");
for(int i = 0; i < 5; i++) {
printf("x.array[%d] = %d
", i, x.array[i]);
}
printf("
");
// if we change one value of x array, those changes apply also to the y, cuz after x=y assign they both point to the same array
x.array[0] = 10;
printf("
////// y.array after x.array[0] was changed ///////////
");
for(int i = 0; i < 5; i++) {
printf(" y.array[%d] = %d
", i, y.array[i]);
}
printf("
");
free(y.array);
return 0;
}
@@MrMits92 That is correct!
23:00 In case it was not mentioned, you also get a memory leak on the x.array block, and a duplicate reference to the y.array block... Common pitfalls to the begginers...
Yes, we need to watch out for these things. :-)
so structs is a class without functions?
In C, essentially yes. :-) In C++ struct is a lot more like class though, just so you know: learn.microsoft.com/en-us/cpp/cpp/classes-and-structs-cpp?view=msvc-170
whatever anything
11:23
Do you have a question? 🙂
you dont have enough place in char name for osas
whatever anything I do or did
whatever anything I know or knew or do or did and in 7:14 or more you did something you know what I mean
I am not sure when exactly and whatver anythign
Anything*
whatever anything I do or did or anything
I absolutely love these videos, but I think it's important to point out that when you use malloc, you have to free the space before reassigning the pointer, or a memory leak is created. And I only say this because the dementia patients in the Whitehouse just urged us all to stop using these languages for this reason.
You're right, I was trying to stay focused on structs in this video and keeping it to a reasonable time, I've made note of this and pinned a link to this other video on memory leaks now: th-cam.com/video/lQCLAKfcYI4/w-d-xo.html
The popup tools in your editor are too distracting.
Just fo us tf 😂
You teach very good undoubtedly but if you could give separate examples of every items instead of massing everything in a single code, it would be better to understand for us.... You can copy and paste from the previous code that you needed for the next example but please give separate examples instead of giving a very long example.
why is x.array[0] in the last example not also equal to 10 like the y array?
Thanks!
Wow thank you so much for the 'super thanks'!!! :-D
Amazing
I'm glad you liked it! :-)