what's exactly the string of “^A” is?
I run my code on an online judgement. I log the string, key. Below is my code:
fprintf(stderr, "key=%s, and key.size()=%dn", key.c_str(), key.size());
But the result is this:
key=^A, and key.size()=8
I want to what is the ^A represent in ascii. ^A's size is 2 rather than 8, but it shows that it is 8. I view the result by vim, and the log_file is encoded by UTF-8. Why?
c++ character ascii
edited Nov 17 '18 at 10:40
Spikatrix
17.4k62660
asked Nov 17 '18 at 8:38
lxclxc
218
|
show 8 more comments
I run my code on an online judgement. I log the string, key. Below is my code:
fprintf(stderr, "key=%s, and key.size()=%dn", key.c_str(), key.size());
But the result is this:
key=^A, and key.size()=8
I want to what is the ^A represent in ascii. ^A's size is 2 rather than 8, but it shows that it is 8. I view the result by vim, and the log_file is encoded by UTF-8. Why?
c++ character ascii
edited Nov 17 '18 at 10:40
Spikatrix
17.4k62660
asked Nov 17 '18 at 8:38
lxclxc
218
What value the c_str() is returning actually ? Share the structure Key, and the values you are storing to it's data members.
– Mazhar
Nov 17 '18 at 8:40
What iskey?
– tkausl
Nov 17 '18 at 8:41
@Mazhar c_str() return const char *.
– lxc
Nov 17 '18 at 8:42
1
@Mazharc_str()is C++. I've retagged the question. To the OP: Please use relevant tags only
– Spikatrix
Nov 17 '18 at 10:41
1
@Mazhar I have solve it by myself. Happy.
– lxc
Nov 17 '18 at 13:03
|
show 8 more comments
I run my code on an online judgement. I log the string, key. Below is my code:
fprintf(stderr, "key=%s, and key.size()=%dn", key.c_str(), key.size());
But the result is this:
key=^A, and key.size()=8
I want to what is the ^A represent in ascii. ^A's size is 2 rather than 8, but it shows that it is 8. I view the result by vim, and the log_file is encoded by UTF-8. Why?
c++ character ascii
edited Nov 17 '18 at 10:40
Spikatrix
17.4k62660
asked Nov 17 '18 at 8:38
lxclxc
218
I run my code on an online judgement. I log the string, key. Below is my code:
fprintf(stderr, "key=%s, and key.size()=%dn", key.c_str(), key.size());
But the result is this:
key=^A, and key.size()=8
I want to what is the ^A represent in ascii. ^A's size is 2 rather than 8, but it shows that it is 8. I view the result by vim, and the log_file is encoded by UTF-8. Why?
c++ character ascii
c++ character ascii
edited Nov 17 '18 at 10:40
Spikatrix
17.4k62660
asked Nov 17 '18 at 8:38
lxclxc
218
edited Nov 17 '18 at 10:40
Spikatrix
17.4k62660
asked Nov 17 '18 at 8:38
lxclxc
218
edited Nov 17 '18 at 10:40
Spikatrix
17.4k62660
edited Nov 17 '18 at 10:40
Spikatrix
17.4k62660
edited Nov 17 '18 at 10:40
Spikatrix
17.4k62660
17.4k62660
asked Nov 17 '18 at 8:38
lxclxc
218
asked Nov 17 '18 at 8:38
lxclxc
218
asked Nov 17 '18 at 8:38
lxclxc
218
218
What value the c_str() is returning actually ? Share the structure Key, and the values you are storing to it's data members.
– Mazhar
Nov 17 '18 at 8:40
What iskey?
– tkausl
Nov 17 '18 at 8:41
@Mazhar c_str() return const char *.
– lxc
Nov 17 '18 at 8:42
1
@Mazharc_str()is C++. I've retagged the question. To the OP: Please use relevant tags only
– Spikatrix
Nov 17 '18 at 10:41
1
@Mazhar I have solve it by myself. Happy.
– lxc
Nov 17 '18 at 13:03
|
show 8 more comments
What value the c_str() is returning actually ? Share the structure Key, and the values you are storing to it's data members.
– Mazhar
Nov 17 '18 at 8:40
What iskey?
– tkausl
Nov 17 '18 at 8:41
@Mazhar c_str() return const char *.
– lxc
Nov 17 '18 at 8:42
1
@Mazharc_str()is C++. I've retagged the question. To the OP: Please use relevant tags only
– Spikatrix
Nov 17 '18 at 10:41
1
@Mazhar I have solve it by myself. Happy.
– lxc
Nov 17 '18 at 13:03
What value the c_str() is returning actually ? Share the structure Key, and the values you are storing to it's data members.
– Mazhar
Nov 17 '18 at 8:40
What value the c_str() is returning actually ? Share the structure Key, and the values you are storing to it's data members.
– Mazhar
Nov 17 '18 at 8:40
What is
key ?– tkausl
Nov 17 '18 at 8:41
What is
key ?– tkausl
Nov 17 '18 at 8:41
@Mazhar c_str() return const char *.
– lxc
Nov 17 '18 at 8:42
@Mazhar c_str() return const char *.
– lxc
Nov 17 '18 at 8:42
1
1
@Mazhar
c_str() is C++. I've retagged the question. To the OP: Please use relevant tags only– Spikatrix
Nov 17 '18 at 10:41
@Mazhar
c_str() is C++. I've retagged the question. To the OP: Please use relevant tags only– Spikatrix
Nov 17 '18 at 10:41
1
1
@Mazhar I have solve it by myself. Happy.
– lxc
Nov 17 '18 at 13:03
@Mazhar I have solve it by myself. Happy.
– lxc
Nov 17 '18 at 13:03
|
show 8 more comments
2 Answers
2
active
oldest
votes
Your viewer is electing to show you the bytes interpreted using a character encoding of its choosing and electing to show the resulting characters in caret notation.
Other viewers could make different choices on both counts or allow you to indicate what you want. For example, control picture characters (␁) instead of caret notation.
For a std:string c_str() is terminated by an additional x00 byte following the actual value. You often use c_str() with functions that expect a string to be x00 terminated. This applies to fprintf. In such cases, what's read ends just before the first x00 seen.
You have several x00 bytes in your string, which, of course, contributes to size() but fprintf will stop right at the first one (and not count it).
answered Nov 17 '18 at 16:19
Tom BlodgetTom Blodget
16.1k22452
Thank you. I know the reason behind the phenomenon.
– lxc
Nov 18 '18 at 7:49
add a comment |
I have solve it by myself. If you write a std::string "x01x00x00x00x00end" to a file and open it with vim later, you will get '^A'.
This is my test code:
string sss("x01x00x00x00x00end");
ofstream of("of.txt");
for (int i=0; i<sss.size(); i++) {
of.put(sss[i]);
}
of.close();
After I open the file "of.txt", I saw "^A";
answered Nov 17 '18 at 13:00
lxclxc
218
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
Your viewer is electing to show you the bytes interpreted using a character encoding of its choosing and electing to show the resulting characters in caret notation.
Other viewers could make different choices on both counts or allow you to indicate what you want. For example, control picture characters (␁) instead of caret notation.
For a std:string c_str() is terminated by an additional x00 byte following the actual value. You often use c_str() with functions that expect a string to be x00 terminated. This applies to fprintf. In such cases, what's read ends just before the first x00 seen.
You have several x00 bytes in your string, which, of course, contributes to size() but fprintf will stop right at the first one (and not count it).
answered Nov 17 '18 at 16:19
Tom BlodgetTom Blodget
16.1k22452
Thank you. I know the reason behind the phenomenon.
– lxc
Nov 18 '18 at 7:49
add a comment |
Your viewer is electing to show you the bytes interpreted using a character encoding of its choosing and electing to show the resulting characters in caret notation.
Other viewers could make different choices on both counts or allow you to indicate what you want. For example, control picture characters (␁) instead of caret notation.
For a std:string c_str() is terminated by an additional x00 byte following the actual value. You often use c_str() with functions that expect a string to be x00 terminated. This applies to fprintf. In such cases, what's read ends just before the first x00 seen.
You have several x00 bytes in your string, which, of course, contributes to size() but fprintf will stop right at the first one (and not count it).
answered Nov 17 '18 at 16:19
Tom BlodgetTom Blodget
16.1k22452
Thank you. I know the reason behind the phenomenon.
– lxc
Nov 18 '18 at 7:49
add a comment |
Your viewer is electing to show you the bytes interpreted using a character encoding of its choosing and electing to show the resulting characters in caret notation.
Other viewers could make different choices on both counts or allow you to indicate what you want. For example, control picture characters (␁) instead of caret notation.
For a std:string c_str() is terminated by an additional x00 byte following the actual value. You often use c_str() with functions that expect a string to be x00 terminated. This applies to fprintf. In such cases, what's read ends just before the first x00 seen.
You have several x00 bytes in your string, which, of course, contributes to size() but fprintf will stop right at the first one (and not count it).
answered Nov 17 '18 at 16:19
Tom BlodgetTom Blodget
16.1k22452
Your viewer is electing to show you the bytes interpreted using a character encoding of its choosing and electing to show the resulting characters in caret notation.
Other viewers could make different choices on both counts or allow you to indicate what you want. For example, control picture characters (␁) instead of caret notation.
For a std:string c_str() is terminated by an additional x00 byte following the actual value. You often use c_str() with functions that expect a string to be x00 terminated. This applies to fprintf. In such cases, what's read ends just before the first x00 seen.
You have several x00 bytes in your string, which, of course, contributes to size() but fprintf will stop right at the first one (and not count it).
answered Nov 17 '18 at 16:19
Tom BlodgetTom Blodget
16.1k22452
edited Nov 17 '18 at 18:09
answered Nov 17 '18 at 16:19
Tom BlodgetTom Blodget
16.1k22452
answered Nov 17 '18 at 16:19
Tom BlodgetTom Blodget
16.1k22452
answered Nov 17 '18 at 16:19
Tom BlodgetTom Blodget
16.1k22452
16.1k22452
Thank you. I know the reason behind the phenomenon.
– lxc
Nov 18 '18 at 7:49
add a comment |
Thank you. I know the reason behind the phenomenon.
– lxc
Nov 18 '18 at 7:49
Thank you. I know the reason behind the phenomenon.
– lxc
Nov 18 '18 at 7:49
Thank you. I know the reason behind the phenomenon.
– lxc
Nov 18 '18 at 7:49
add a comment |
I have solve it by myself. If you write a std::string "x01x00x00x00x00end" to a file and open it with vim later, you will get '^A'.
This is my test code:
string sss("x01x00x00x00x00end");
ofstream of("of.txt");
for (int i=0; i<sss.size(); i++) {
of.put(sss[i]);
}
of.close();
After I open the file "of.txt", I saw "^A";
answered Nov 17 '18 at 13:00
lxclxc
218
add a comment |
I have solve it by myself. If you write a std::string "x01x00x00x00x00end" to a file and open it with vim later, you will get '^A'.
This is my test code:
string sss("x01x00x00x00x00end");
ofstream of("of.txt");
for (int i=0; i<sss.size(); i++) {
of.put(sss[i]);
}
of.close();
After I open the file "of.txt", I saw "^A";
answered Nov 17 '18 at 13:00
lxclxc
218
add a comment |
I have solve it by myself. If you write a std::string "x01x00x00x00x00end" to a file and open it with vim later, you will get '^A'.
This is my test code:
string sss("x01x00x00x00x00end");
ofstream of("of.txt");
for (int i=0; i<sss.size(); i++) {
of.put(sss[i]);
}
of.close();
After I open the file "of.txt", I saw "^A";
answered Nov 17 '18 at 13:00
lxclxc
218
I have solve it by myself. If you write a std::string "x01x00x00x00x00end" to a file and open it with vim later, you will get '^A'.
This is my test code:
string sss("x01x00x00x00x00end");
ofstream of("of.txt");
for (int i=0; i<sss.size(); i++) {
of.put(sss[i]);
}
of.close();
After I open the file "of.txt", I saw "^A";
answered Nov 17 '18 at 13:00
lxclxc
218
edited Nov 18 '18 at 7:47
answered Nov 17 '18 at 13:00
lxclxc
218
answered Nov 17 '18 at 13:00
lxclxc
218
answered Nov 17 '18 at 13:00
lxclxc
218
218
add a comment |
add a comment |
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What value the c_str() is returning actually ? Share the structure Key, and the values you are storing to it's data members.
– Mazhar
Nov 17 '18 at 8:40
What is
key?– tkausl
Nov 17 '18 at 8:41
@Mazhar c_str() return const char *.
– lxc
Nov 17 '18 at 8:42
1
@Mazhar
c_str()is C++. I've retagged the question. To the OP: Please use relevant tags only– Spikatrix
Nov 17 '18 at 10:41
1
@Mazhar I have solve it by myself. Happy.
– lxc
Nov 17 '18 at 13:03