#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <io.h>

/* This program reads the files whose naems are specified on
   the command line, concatenates them, and writes the result
   to `merged.dat'.

   Can be used instead of `cat', or `copy /b ... + ... + ...'
*/

typedef char * str;
typedef int logical;

#define oops(s) { fprintf(stderr, "%s\n", s); exit(1); }

const int LB=16384;

int main(int argc, str argv[]) {
  FILE *f, *g;
  char *buffer;
  char *p, *outname = "merged.dat";
  int d, i;

  if (argc < 2) {
     printf("Use:\n");
     printf("\t%s <file1> <file2> ...\n", argv[0]);
     printf("to concatenate the files and write the output to `%s'\n",
	    outname);
     exit(0);
  }

  buffer = (char*)malloc(LB);
  if (!buffer) oops("Out of memory!");

  if (access(outname, 0) == 0) {
    fprintf(stderr, "File %s already exists. Please remove it first\n",
	    outname);
    exit(1);
  }
  g = fopen(outname, "wb");
  if (!g) {
    fprintf(stderr, "Can't write to the file `%s'\n", outname);
    exit(1);
  }
  for(i=1; i<argc; i++) {
    f = fopen( argv[i], "rb");
    if (!f) {
       fprintf(stderr,
	 "Can't open file `%s'; continuing with the next file\n", argv[i]);
    }
    while( d = fread( buffer, 1, LB, f), d>0) fwrite( buffer,1, d, g);
    fclose(f);
  }
  return 0;
}