Understanding the need for fflush() and problems associated with it

Question

Below is sample code for using fflush():

#include 
#include 
#include 
#include 

void flush(FILE *         


        

Answer 1

fflush() empties the buffers related to the stream. if you e.g. let a user input some data in a very shot timespan (milliseconds) and write some stuff into a file, the writing and reading buffers may have some "reststuff" remaining in themselves. you call fflush() then to empty all the buffers and force standard outputs to be sure the next input you get is what the user pressed then.

reference: http://www.cplusplus.com/reference/cstdio/fflush/