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sscanf: get first and last token in a string

开发者 https://www.devze.com 2023-03-15 20:04 出处:网络
Is it possible by using sscanf to get the first token then skip some tokens and then get the last one?

Is it possible by using sscanf to get the first token then skip some tokens and then get the last one?

For example, the output of /bin/ps -fu1000

  cm  2249  1548   0   0:00.00 ttys001    0:开发者_StackOverflow00.01 man sscanf

I have tried:

sscanf(line, "%s %[^\n]", user, cmd);

The result should be:

user = "cm";
cmd = "man sscanf":

But it does not work.


Yes, but it's ugly and can't be error checked properly.

/* assuming `user` and `cmd` are character arrays defined with 42 bytes */
if (sscanf(line, "%41s%*s%*s%*s%*s%*s%*s %41[^\n]", user, cmd) != 2) {
    /* handle error */
} else {
    /* hopefully ok */
}

You can replace some of the %*s with %*d. The * means that the item is parsed but not assigned anywhere (it is ignored).

In the statement, there are 6 ignored items corresponding to the items between "cm" and "man sscanf" in your example.

Also note I limited the input to 41 characters in the scanf itself. Make sure you do not write outside the objects.


EDIT: I added a space before the last conversion because, unlike %s or %d conversions, the %[ conversion does not skip leading whitespace.


Perhaps you'd better look at strtok

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