Question

I have a file, in which each line contains several words that are separated by variable amount of whitespace characters (spaces and tabs). For example:

do that param1   param2  param3
do   this   param1

(The number of words in a line is unknown in advance and is unbounded)

I’m looking for a way to parse such a line in plain C, so that I’ll have a pointer to string containing the first word, a pointer to a string containing the second word, and a pointer to a string containing everything else (that is – all of the line, except the first two words). The idea is that the “rest of the line” string will be further parsed by a callback function, determined by the first two words).

Getting the first two words is easy enough (a simple sscanf), but I have no idea how to get the “rest of the line” pointer (As sscanf stops at whitespace, and I don’t know the amount of whitespace before the first word, and between the first and the second word).

Any idea will be greatly appreciated.

Answer 1

You can use sscanf for the rest of the line as well. You just use a “scanset” conversion instead of a string conversion:

char word1[256], word2[256], remainder[1024];

sscanf(input_line, "%255s %255s %1023[^\n]", word1, word2, remainder);