Making Format String with sprintf

Question

I want to create a format string that will be used in scanf by specifying a MAX_LENGTH for a string input. What I have is the following but the compiler says it's wrong:

const int MAX_LENGTH = 50;
char format[9];

sprintf(format, "\%%d[^\n]s", MAX_LENGTH);

The compiler says that the data argument is not used by the format string. The first % should be escaped, and the second one is part of the %d which should be read in from MAX_LENGTH . How do I accomplish this? By the way, the format string should read at most MAX_LENGTH characters until a newline is reached.

Answer 1

应使用%% ， 而非 \\%来转义％符号。