#include<stdio.h>
#include<stdlib.h>
#include<unistd.h>
#include<sys/types.h>
#include<fcntl.h>

/* file copy in C - binary version. copies argv[1] to argv[2] */

#define BUFSIZE 1024

int main(int argc, char* argv[])
{
  int infd, outfd;   // file descriptors
  int n = BUFSIZE; // number of bytes actually read each time
  unsigned char /*byte*/ buffer[BUFSIZE];
  if (argc != 3) { perror("wrong number of arguments\n"); exit(1); }
  
  infd = open(argv[1],O_RDONLY,0);
  outfd = open(argv[2],O_WRONLY | O_CREAT | O_TRUNC,0755); 
                       // 0755 is file permission, as used by chmod
  while (n>0)
    {
      n = read(infd,buffer,BUFSIZE); // reads UP TO BUFSIZE bytes
      if (n>0) write(outfd,buffer,n);
    }

  close(infd);
  close(outfd);
  exit(0);
}


/* copy program in c using streams - not recommended for beginners*/

int main2(int argc, char *argv[])
{ 
  char b;   // character buffer
  int infd, outfd;   // file descriptors
  int result = EOF + 1;   // something not EOF
  FILE *infile;
  FILE *outfile;
  infile = fopen(*++argv,"r");
  outfile = fopen(*++argv,"w");

  while (!(result == EOF))
   {  result = fscanf(infile,"%c",&b);   // copy char by char
      
      // need to use gets
      if (!(result == EOF))
        fprintf(outfile,"%c",(char)b);

   }

  /*  version using fgets - better be good with C strings!
  
      char buffer[BUFSIZE];
      char *rs;     // returned by fgets, which will be null on EOF
      rs = buffer;  // so it's not null initially
      while (rs != NULL)
      {
         rs = fgets(buffer,BUFSIZE,infile);
	 buffer[BUFSIZE-1] = 0;  // extra safety - make sure string terminated
	 if (rs) fprintf(outfile,"%s",buffer);
      }
   */

  fclose(infile);
  fclose(outfile);

  exit(0);
} //main