Jagged array implementation in C- error: expected ';' at the end of declaration list
I wrote a piece of C code as below:-
typedef struct {
unsigned int buffer_ctrl[4];
unsigned int buffer1[10];
unsigned int buffer2[40];
unsigned int buffer3[20];
unsigned int buffer4[15];
unsigned int *buffer_ptr[4] = {buffer1, buffer2, buffer3, buffer4};
unsigned int canary[4];
} buffer_t;
I wrote this in a header file which I included in a main code. I had read up a lot of examples on jagged array in C and thought this would work just fine. One of the links was Do jagged arrays exist in C/C++?.
However, when I compile I get the error "expected ';' at end of declaration lsit". Can someone please help explain what might be the error here?
Thanks!
c jagged-arrays
asked Nov 13 '18 at 4:57
Siddharth Kabra
62
|
show 1 more comment
I wrote a piece of C code as below:-
typedef struct {
unsigned int buffer_ctrl[4];
unsigned int buffer1[10];
unsigned int buffer2[40];
unsigned int buffer3[20];
unsigned int buffer4[15];
unsigned int *buffer_ptr[4] = {buffer1, buffer2, buffer3, buffer4};
unsigned int canary[4];
} buffer_t;
I wrote this in a header file which I included in a main code. I had read up a lot of examples on jagged array in C and thought this would work just fine. One of the links was Do jagged arrays exist in C/C++?.
However, when I compile I get the error "expected ';' at end of declaration lsit". Can someone please help explain what might be the error here?
Thanks!
c jagged-arrays
asked Nov 13 '18 at 4:57
Siddharth Kabra
62
1
It will exceptunsigned int *buffer_ptr[4] = {buffer1, buffer2, buffer3, buffer4};-- you can't initialize member of a struct at the time of definition. (but you could use aunionwithin thestructto essentially do the same).
– David C. Rankin
Nov 13 '18 at 5:02
1
Inside a structure? That would not work, I believe.
– Sourav Ghosh
Nov 13 '18 at 5:03
1
@DavidC.Rankin You mean can't - right?
– Sourav Ghosh
Nov 13 '18 at 5:03
1
Yes, right -- you can't (that was meant to say all would work "except" ..).
– David C. Rankin
Nov 13 '18 at 5:04
Please copy-paste the error message verbatim. This does not help anyone if you typo the error message!
– Antti Haapala
Nov 13 '18 at 5:36
|
show 1 more comment
I wrote a piece of C code as below:-
typedef struct {
unsigned int buffer_ctrl[4];
unsigned int buffer1[10];
unsigned int buffer2[40];
unsigned int buffer3[20];
unsigned int buffer4[15];
unsigned int *buffer_ptr[4] = {buffer1, buffer2, buffer3, buffer4};
unsigned int canary[4];
} buffer_t;
I wrote this in a header file which I included in a main code. I had read up a lot of examples on jagged array in C and thought this would work just fine. One of the links was Do jagged arrays exist in C/C++?.
However, when I compile I get the error "expected ';' at end of declaration lsit". Can someone please help explain what might be the error here?
Thanks!
c jagged-arrays
asked Nov 13 '18 at 4:57
Siddharth Kabra
62
I wrote a piece of C code as below:-
typedef struct {
unsigned int buffer_ctrl[4];
unsigned int buffer1[10];
unsigned int buffer2[40];
unsigned int buffer3[20];
unsigned int buffer4[15];
unsigned int *buffer_ptr[4] = {buffer1, buffer2, buffer3, buffer4};
unsigned int canary[4];
} buffer_t;
I wrote this in a header file which I included in a main code. I had read up a lot of examples on jagged array in C and thought this would work just fine. One of the links was Do jagged arrays exist in C/C++?.
However, when I compile I get the error "expected ';' at end of declaration lsit". Can someone please help explain what might be the error here?
Thanks!
c jagged-arrays
c jagged-arrays
asked Nov 13 '18 at 4:57
Siddharth Kabra
62
asked Nov 13 '18 at 4:57
Siddharth Kabra
62
edited Nov 13 '18 at 18:51
asked Nov 13 '18 at 4:57
Siddharth Kabra
62
asked Nov 13 '18 at 4:57
Siddharth Kabra
62
asked Nov 13 '18 at 4:57
Siddharth Kabra
62
62
1
It will exceptunsigned int *buffer_ptr[4] = {buffer1, buffer2, buffer3, buffer4};-- you can't initialize member of a struct at the time of definition. (but you could use aunionwithin thestructto essentially do the same).
– David C. Rankin
Nov 13 '18 at 5:02
1
Inside a structure? That would not work, I believe.
– Sourav Ghosh
Nov 13 '18 at 5:03
1
@DavidC.Rankin You mean can't - right?
– Sourav Ghosh
Nov 13 '18 at 5:03
1
Yes, right -- you can't (that was meant to say all would work "except" ..).
– David C. Rankin
Nov 13 '18 at 5:04
Please copy-paste the error message verbatim. This does not help anyone if you typo the error message!
– Antti Haapala
Nov 13 '18 at 5:36
|
show 1 more comment
1
It will exceptunsigned int *buffer_ptr[4] = {buffer1, buffer2, buffer3, buffer4};-- you can't initialize member of a struct at the time of definition. (but you could use aunionwithin thestructto essentially do the same).
– David C. Rankin
Nov 13 '18 at 5:02
1
Inside a structure? That would not work, I believe.
– Sourav Ghosh
Nov 13 '18 at 5:03
1
@DavidC.Rankin You mean can't - right?
– Sourav Ghosh
Nov 13 '18 at 5:03
1
Yes, right -- you can't (that was meant to say all would work "except" ..).
– David C. Rankin
Nov 13 '18 at 5:04
Please copy-paste the error message verbatim. This does not help anyone if you typo the error message!
– Antti Haapala
Nov 13 '18 at 5:36
1
1
It will except
unsigned int *buffer_ptr[4] = {buffer1, buffer2, buffer3, buffer4}; -- you can't initialize member of a struct at the time of definition. (but you could use a union within the struct to essentially do the same).– David C. Rankin
Nov 13 '18 at 5:02
It will except
unsigned int *buffer_ptr[4] = {buffer1, buffer2, buffer3, buffer4}; -- you can't initialize member of a struct at the time of definition. (but you could use a union within the struct to essentially do the same).– David C. Rankin
Nov 13 '18 at 5:02
1
1
Inside a structure? That would not work, I believe.
– Sourav Ghosh
Nov 13 '18 at 5:03
Inside a structure? That would not work, I believe.
– Sourav Ghosh
Nov 13 '18 at 5:03
1
1
@DavidC.Rankin You mean can't - right?
– Sourav Ghosh
Nov 13 '18 at 5:03
@DavidC.Rankin You mean can't - right?
– Sourav Ghosh
Nov 13 '18 at 5:03
1
1
Yes, right -- you can't (that was meant to say all would work "except" ..).
– David C. Rankin
Nov 13 '18 at 5:04
Yes, right -- you can't (that was meant to say all would work "except" ..).
– David C. Rankin
Nov 13 '18 at 5:04
Please copy-paste the error message verbatim. This does not help anyone if you typo the error message!
– Antti Haapala
Nov 13 '18 at 5:36
Please copy-paste the error message verbatim. This does not help anyone if you typo the error message!
– Antti Haapala
Nov 13 '18 at 5:36
|
show 1 more comment
1 Answer
1
active
oldest
votes
You cannot assign to buffer_ptr within the definition of the buffer_t structure itself. You have to define a variable of the type buffer_t first and then assign to it.
You can do something like this:
buffer_t bt = {
.buffer_ptr[0] = bt.buffer1,
.buffer_ptr[1] = bt.buffer2,
.buffer_ptr[2] = bt.buffer3,
.buffer_ptr[3] = bt.buffer4
};
answered Nov 13 '18 at 5:16
P.W
11.4k3842
There generally isn't a good reason to permanently store an array that is so easy to calculate, though. You can create such an array when you need it, and save memory when you don't.
– YoYoYonnY
Nov 13 '18 at 18:55
add a comment |
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1 Answer
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oldest
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1 Answer
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active
oldest
votes
active
oldest
votes
active
oldest
votes
You cannot assign to buffer_ptr within the definition of the buffer_t structure itself. You have to define a variable of the type buffer_t first and then assign to it.
You can do something like this:
buffer_t bt = {
.buffer_ptr[0] = bt.buffer1,
.buffer_ptr[1] = bt.buffer2,
.buffer_ptr[2] = bt.buffer3,
.buffer_ptr[3] = bt.buffer4
};
answered Nov 13 '18 at 5:16
P.W
11.4k3842
There generally isn't a good reason to permanently store an array that is so easy to calculate, though. You can create such an array when you need it, and save memory when you don't.
– YoYoYonnY
Nov 13 '18 at 18:55
add a comment |
You cannot assign to buffer_ptr within the definition of the buffer_t structure itself. You have to define a variable of the type buffer_t first and then assign to it.
You can do something like this:
buffer_t bt = {
.buffer_ptr[0] = bt.buffer1,
.buffer_ptr[1] = bt.buffer2,
.buffer_ptr[2] = bt.buffer3,
.buffer_ptr[3] = bt.buffer4
};
answered Nov 13 '18 at 5:16
P.W
11.4k3842
There generally isn't a good reason to permanently store an array that is so easy to calculate, though. You can create such an array when you need it, and save memory when you don't.
– YoYoYonnY
Nov 13 '18 at 18:55
add a comment |
You cannot assign to buffer_ptr within the definition of the buffer_t structure itself. You have to define a variable of the type buffer_t first and then assign to it.
You can do something like this:
buffer_t bt = {
.buffer_ptr[0] = bt.buffer1,
.buffer_ptr[1] = bt.buffer2,
.buffer_ptr[2] = bt.buffer3,
.buffer_ptr[3] = bt.buffer4
};
answered Nov 13 '18 at 5:16
P.W
11.4k3842
You cannot assign to buffer_ptr within the definition of the buffer_t structure itself. You have to define a variable of the type buffer_t first and then assign to it.
You can do something like this:
buffer_t bt = {
.buffer_ptr[0] = bt.buffer1,
.buffer_ptr[1] = bt.buffer2,
.buffer_ptr[2] = bt.buffer3,
.buffer_ptr[3] = bt.buffer4
};
answered Nov 13 '18 at 5:16
P.W
11.4k3842
answered Nov 13 '18 at 5:16
P.W
11.4k3842
answered Nov 13 '18 at 5:16
P.W
11.4k3842
answered Nov 13 '18 at 5:16
P.W
11.4k3842
11.4k3842
There generally isn't a good reason to permanently store an array that is so easy to calculate, though. You can create such an array when you need it, and save memory when you don't.
– YoYoYonnY
Nov 13 '18 at 18:55
add a comment |
There generally isn't a good reason to permanently store an array that is so easy to calculate, though. You can create such an array when you need it, and save memory when you don't.
– YoYoYonnY
Nov 13 '18 at 18:55
There generally isn't a good reason to permanently store an array that is so easy to calculate, though. You can create such an array when you need it, and save memory when you don't.
– YoYoYonnY
Nov 13 '18 at 18:55
There generally isn't a good reason to permanently store an array that is so easy to calculate, though. You can create such an array when you need it, and save memory when you don't.
– YoYoYonnY
Nov 13 '18 at 18:55
add a comment |
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1
It will except
unsigned int *buffer_ptr[4] = {buffer1, buffer2, buffer3, buffer4};-- you can't initialize member of a struct at the time of definition. (but you could use aunionwithin thestructto essentially do the same).– David C. Rankin
Nov 13 '18 at 5:02
1
Inside a structure? That would not work, I believe.
– Sourav Ghosh
Nov 13 '18 at 5:03
1
@DavidC.Rankin You mean can't - right?
– Sourav Ghosh
Nov 13 '18 at 5:03
1
Yes, right -- you can't (that was meant to say all would work "except" ..).
– David C. Rankin
Nov 13 '18 at 5:04
Please copy-paste the error message verbatim. This does not help anyone if you typo the error message!
– Antti Haapala
Nov 13 '18 at 5:36