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Your pointer function is uninitialized. From some documentation pages for scanf at https://man7.org/linux/man-pages/man3/scanf.3.html : s Matches a sequence of non-white-space characters; the...
Answer
#3: Post edited
by
elgonzo
·
2021-06-30T10:28:31Z (almost 3 years ago)
Your pointer function is uninitialized.- From some documentation pages for `scanf`
- at https://man7.org/linux/man-pages/man3/scanf.3.html :
- > s<br>
- >Matches a sequence of non-white-space characters; **the next
- pointer must be a pointer to the initial element of a
- character array that is long enough to hold the input
- sequence and the terminating null byte ('\0')**, which is
- added automatically. The input string stops at white
- space or at the maximum field width, whichever occurs
- first.
- and at https://www.cplusplus.com/reference/cstdio/scanf/ :
- > ... (additional arguments)<br>
- >Depending on the format string, the function may expect a sequence of additional arguments, each containing a pointer to **allocated storage** where the interpretation of the extracted characters is stored with the appropriate type.<br>
- (emphasis mine)
- <br>
- The simplest way is probably to use a char array, and limit the field width of the `%s` format specifier to the size of the char array (minus the null terminator):
- ```c
- char function [80];
- scanf("%79s", function);
- ```
- <br>
- (P.S.: I don't know whether the code example in your question is really the cause of the issue you experience. I have doubts, as i would rather expect the program crashing when using an uninitialized pointer like that. But hey, it's the code you have identified as being the cause of the problem, so i will go with that...)
- Your pointer `function` is uninitialized.
- From some documentation pages for `scanf`
- at https://man7.org/linux/man-pages/man3/scanf.3.html :
- > s<br>
- >Matches a sequence of non-white-space characters; **the next
- pointer must be a pointer to the initial element of a
- character array that is long enough to hold the input
- sequence and the terminating null byte ('\0')**, which is
- added automatically. The input string stops at white
- space or at the maximum field width, whichever occurs
- first.
- and at https://www.cplusplus.com/reference/cstdio/scanf/ :
- > ... (additional arguments)<br>
- >Depending on the format string, the function may expect a sequence of additional arguments, each containing a pointer to **allocated storage** where the interpretation of the extracted characters is stored with the appropriate type.<br>
- (emphasis mine)
- <br>
- The simplest way is probably to use a char array, and limit the field width of the `%s` format specifier to the size of the char array (minus the null terminator):
- ```c
- char function [80];
- scanf("%79s", function);
- ```
- <br>
- (P.S.: I don't know whether the code example in your question is really the cause of the issue you experience. I have doubts, as i would rather expect the program crashing when using an uninitialized pointer like that. But hey, it's the code you have identified as being the cause of the problem, so i will go with that...)
#2: Post edited
by
elgonzo
·
2021-06-30T10:12:45Z (almost 3 years ago)
- Your pointer function is uninitialized.
- From some documentation pages for `scanf`
- at https://man7.org/linux/man-pages/man3/scanf.3.html :
- > s<br>
- >Matches a sequence of non-white-space characters; **the next
- pointer must be a pointer to the initial element of a
- character array that is long enough to hold the input
- sequence and the terminating null byte ('\0')**, which is
- added automatically. The input string stops at white
- space or at the maximum field width, whichever occurs
- first.
- and at https://www.cplusplus.com/reference/cstdio/scanf/ :
- > ... (additional arguments)<br>
- >Depending on the format string, the function may expect a sequence of additional arguments, each containing a pointer to **allocated storage** where the interpretation of the extracted characters is stored with the appropriate type.<br>
- (emphasis mine)
- <br>
- The simplest way is probably to use a char array, and limit the field width of the `%s` format specifier to the size of the char array (minus the null terminator):
- ```c
- char function [80];
- scanf("%79s", function);
- ```
- <br>
(P.S.: I don't know whether the code example in your question is really the cause of the issue you experience. I have doubts, as i would rather expect the program crashing when using an uninitilized pointer like that. But hey, it's the code you have identified as being the cause of the problem, so i will go with that...)
- Your pointer function is uninitialized.
- From some documentation pages for `scanf`
- at https://man7.org/linux/man-pages/man3/scanf.3.html :
- > s<br>
- >Matches a sequence of non-white-space characters; **the next
- pointer must be a pointer to the initial element of a
- character array that is long enough to hold the input
- sequence and the terminating null byte ('\0')**, which is
- added automatically. The input string stops at white
- space or at the maximum field width, whichever occurs
- first.
- and at https://www.cplusplus.com/reference/cstdio/scanf/ :
- > ... (additional arguments)<br>
- >Depending on the format string, the function may expect a sequence of additional arguments, each containing a pointer to **allocated storage** where the interpretation of the extracted characters is stored with the appropriate type.<br>
- (emphasis mine)
- <br>
- The simplest way is probably to use a char array, and limit the field width of the `%s` format specifier to the size of the char array (minus the null terminator):
- ```c
- char function [80];
- scanf("%79s", function);
- ```
- <br>
- (P.S.: I don't know whether the code example in your question is really the cause of the issue you experience. I have doubts, as i would rather expect the program crashing when using an uninitialized pointer like that. But hey, it's the code you have identified as being the cause of the problem, so i will go with that...)
#1: Initial revision
by
elgonzo
·
2021-06-30T10:11:33Z (almost 3 years ago)
Your pointer function is uninitialized.
From some documentation pages for `scanf`
at https://man7.org/linux/man-pages/man3/scanf.3.html :
> s<br>
>Matches a sequence of non-white-space characters; **the next
pointer must be a pointer to the initial element of a
character array that is long enough to hold the input
sequence and the terminating null byte ('\0')**, which is
added automatically. The input string stops at white
space or at the maximum field width, whichever occurs
first.
and at https://www.cplusplus.com/reference/cstdio/scanf/ :
> ... (additional arguments)<br>
>Depending on the format string, the function may expect a sequence of additional arguments, each containing a pointer to **allocated storage** where the interpretation of the extracted characters is stored with the appropriate type.<br>
(emphasis mine)
<br>
The simplest way is probably to use a char array, and limit the field width of the `%s` format specifier to the size of the char array (minus the null terminator):
```c
char function [80];
scanf("%79s", function);
```
<br>
(P.S.: I don't know whether the code example in your question is really the cause of the issue you experience. I have doubts, as i would rather expect the program crashing when using an uninitilized pointer like that. But hey, it's the code you have identified as being the cause of the problem, so i will go with that...)