Answer 1

[^\n] is a kind of regular expression.

[...]: it matches a nonempty sequence of characters from the scanset (a set of characters given by ...).

^ means that the scanset is "negated": it is given by its complement.

^\n: the scanset is all characters except \n.

Furthermore fscanf (and scanf) will read the longest sequence of input characters matching the format.

So scanf("%[^\n]", s); will read all characters until you reach \n (or EOF) and put them in s. It is a common idiom to read a whole line in C.

SOURCE: https://stackoverflow.com/questions/39431924/what-does-n-mean-in-c#39431982

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