09-24-2008
It's not clear (to me) what you are trying to do here: why can you not use fflush to flush a buffer?
Some immediate observations, though:
getchar returns EOF if nothing is read, rather than a NULL pointer, so don't compare its return value to NULL.
Writing to stdin is unlikely to succeed -- check the return value of fputc.
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GETS(3) Linux Programmer's Manual GETS(3)
NAME
fgetc, fgets, getc, getchar, gets, ungetc - input of characters and strings
SYNOPSIS
#include <stdio.h>
int fgetc(FILE *stream);
char *fgets(char *s, int size, FILE *stream);
int getc(FILE *stream);
int getchar(void);
char *gets(char *s);
int ungetc(int c, FILE *stream);
DESCRIPTION
fgetc() reads the next character from stream and returns it as an unsigned char cast to an int, or EOF on end of file or error.
getc() is equivalent to fgetc() except that it may be implemented as a macro which evaluates stream more than once.
getchar() is equivalent to getc(stdin).
gets() reads a line from stdin into the buffer pointed to by s until either a terminating newline or EOF, which it replaces with '