stat

[warney_out]

how to find from a C program if a file has been accessed or not.....and also how to find from the program if a directory exists or not

[Prelude]

What operating system? Judging by your title I'll assume a POSIX compliant system:

#include <sys/stat.h>
#include <unistd.h>
#include <time.h>

#define FILE_NAME "somefile"

int main ( void )
{
  struct stat file_stats;

  if ( stat ( FILE_NAME, &file_stats ) != -1 ) {
    printf ( "%s last accessed on %s", FILE_NAME, ctime ( file_stats.st_atime ) );

    if ( S_ISDIR ( file_stats.st_mode ) )
      printf ( "%s is a directory\n", FILE_NAME );
  }

  return 0;
}