SSCANF ()-Reads data in a string that matches the specified format.
Function Prototypes:
int sscanf (String str, String fmt, mixed var1, mixed var2 ...);
int scanf (const char *format [, argument] ...);
Description
SSCANF is similar to scanf, which is used for input, except that the latter takes a screen (stdin) as the input source, the former with a fixed string as the input source.
Where format can be one or more {%[*] [width] [{h | l | I64 | L}]type | ' | ' \ t ' | ' \ n ' | Non-% symbol}
Note:
1, * can also be used in the format, (that is,%*d and%*s) with an asterisk (*) indicates that skipping this data is not read in. (that is, do not read this data into the parameters)
2. {A|b|c} indicates that a a,b,c is selected, [d], indicating that either D or D may not be available.
3. Width indicates read widths.
4. {H | l | I64 | L}: The size of the parameter, usually h represents a single-byte size,i that represents a 4-byte size (double exception) for a 2-byte size,l, and L64 represents a 8-byte size.
5, type: This is a lot of, is%s,%d and so on.
6. Special:%*[width] [{h | l | I64 | L}]type indicates that the condition is filtered out and no value is written to the target parameter
Support for collection operations:
%[a-z] to match any character in a to Z, greed (as many matches as possible)
%[ab ' matches a, B, ' one member, greed
%[^a] matches any character not a, greed
Note: When the read-in string is an empty string, the SSCANF function does not change the value of the string to be read into.
Example:
1. Common usage.
char buf[512] =;
SSCANF ("123456", "%s", buf);
printf ("%s\n", buf);
The result is: 123456
2. Take a string of the specified length. As in the following example, take a string with a maximum length of 4 bytes.
SSCANF ("123456", "%4s", buf);
printf ("%s\n", buf);
The result is: 1234
3. The string to take to the specified character. As in the following example, the string is encountered until the space is met.
SSCANF ("123456 Abcdedf", "%[^]", buf);
printf ("%s\n", buf);
The result is: 123456
4. Take a string that contains only the specified character set. As in the following example, take a string that contains only 1 to 9 and lowercase letters.
SSCANF ("123456abcdedfBCDEF", "%[1-9a-z]", buf);
printf ("%s\n", buf);
The result is: 123456ABCDEDF
5. The string to be taken to the specified character set. As in the following example, take a string that encounters an uppercase letter.
SSCANF ("123456abcdedfBCDEF", "%[^a-z]", buf);
printf ("%s\n", buf);
The result is: 123456ABCDEDF
6, given a string iios/[email protected], gets/And the string between @, first filter out "iios/", and then send a string of non-' @ ' to BUF
SSCANF ("Iios/[email protected", "%*[^/]/%[^@]", buf);
printf ("%s\n", buf);
The result is: 12DDWDFF
7, given a string "" Hello, World ", only keep the world. (Note: "," followed by a space)
SSCANF ("Hello, World", "%*s%s", buf);
printf ("%s\n", buf);
The result: World
%*s indicates that the first match to the%s is filtered out, that is, Hello is filtered
If there are no spaces, the result is null.
The SSCANF function is very similar to regular expressions, but there is no strong regular expression, so it is recommended to use regular expressions for more complex string handling.
//-------------------------------------------------------
SSCANF, which represents the formatting of input from a string
The above means that from STR, the input number to X is 32700.
Long ago, I thought C had no own split string function, and then I found sscanf; all along, I thought sscanf could only delimit strings with spaces, and now I find I'm wrong.
SSCANF is a run-time function, and the prototype is simple:
int sscanf (
const Char *buffer,
const char *format [,
Argument] ...
);
Its powerful capabilities are reflected in the support for format.
I used to use it to separate strings like this 2006:03:18:
int A, b, C;
SSCANF ("2006:03:18", "%d:%d:%d", A, B, c);
and 2006:03:18-2006:04:18:
Char sztime1[16] = "", sztime2[16] = "";
SSCANF ("2006:03:18-2006:04:18", "%s-%s", sztime1, sztime2);
But then, I need to deal with 2006:03:18-2006:04:18.
Just canceled the '-' on both sides of the space, but broke the%s of the definition of the string.
Do I need to redesign a function to handle such a situation? It's not complicated, but, in order to have a uniform style for all of the code, I need to change a lot of places to replace the existing sscanf with my own split function. I thought I must have done it, and slept with a strong dissatisfaction with sscanf, waking up and finding it unnecessary.
A type field such as%[] in Format-type. If you read a string that is not delimited by a space, you can use%[].
%[] is similar to a regular expression. [A-z] means reading all characters A-Z, [^a-z] means reading all characters except A-Z.
So the problem is solved:
SSCANF ("2006:03:18-2006:04:18", "%[0-9,:]-%[0-9,:]", sztime1, sztime2);
The use of C-language function sscanf ()
