#include <stdio.h>
#include <fcntl.h>

#define BUFFERS  1048576
FILE *fptr;

int fd, fd2;
char buf[BUFFERS+1], *filename[1000], *destname[1000];
size_t maxbuf;
off_t offset;

int main(int argc, char *argv[])
{
  if(argc !=3||argc!=4 )
  {
    printf("%s", "Usage: hw1 ''input filename.ext'' ''output filename.ext'' [buf
fer size]");
    exit(0);
  }
  else
  {
    filename = argv[1];
    destname = argv[2];

    if((fd = open(filename, O_RDONLY)) == -1)
    {
      fprintf("%s", "Error Code hw1-1, Can't open input file");
    }
    else
      if((fd = open(destname, O_CREAT, 0644)) == -1)
      {
        fprintf("%s", "Error Code hw2-2, Can't open output file for writing");
      }
      else
      {
        maxbuf = argc[3];
        fd = open(filename, O_RDONLY);
        fd2 = open(destname, O_WRONLY);
        if(argc == 4)
        {
          int i = 0;
          int j = 0;
          lseek(fd, i, SEEK_END);
          for(i=maxbuf; i>0; i--)
          {
            read(fd, buf, 1)
          }
        }
        else
        {
          read(fd, buf, 1);
          write(fd2, buf);
        }
      }
    }