Using sscanf to parse two strings out
I have a semi xml formatted file that contains line with the following format:
<param name="Distance" value="1000Km" />
The first char in the string is usually a TAB or spaces. I've been using the following to try to parse the two strings out (from name and value):
if(sscanf(lineread, "\t<param name=\"%s\" value=\"%s\" />", name, value) == 1)
{
//do something
}
name and value are char*
Now, the result is always the same: name gets parse (I need to remo开发者_运维问答ve the quotes) and name is always empty. What am I doing wrong?
Thanks, code is appreciated.
Jess.
As usual, a scanset is probably your best answer:
sscanf(lineread, "%*[^\"]\"%[^\"]\"%*[^\"]\"%[^\"]\"", name, value);
Of course, for real code you also want to limit the lengths of the conversions:
#include <stdio.h>
int main() {
char lineread[] = "<param name=\"Distance\" value=\"1000Km\" />";
char name[256], value[256];
sscanf(lineread, "%*[^\"]\"%255[^\"]\"%*[^\"]\"%255[^\"]\"", name, value);
printf("%s\t%s", name, value);
return 0;
}
Edti: BTW, sscanf returns the number of successful conversions, so in your original code, you probably wanted to compare to 2 instead of 1.
Edit2: This much: %*[^\"]\"
means "read and ignore characters other than a quote mark", then read and skip across a quote mark. The next %255[^\"]\"
means "read up to 255 characters other than a quote mark, then read and skip across a quote mark. That whole pattern is then repeated to read the second string.
The problem with the original code was that %s
stops only after seeing a space. Hence, name
gets Distance"
not Distance
as expected.
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