#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
int main(int argc, char **argv) {
  if (argc != 3) { fprintf(stderr, "Wrong argument count!\n"); return 2; }

  int a = open(argv[1], O_RDONLY);
  if (a == -1) { perror("Opening the first file failed"); return 2; }
  
  int b = open(argv[2], O_RDONLY);
  if (b == -1) { perror("Opening the second file failed"); close(a); return 2; }

  char bufA[256], bufB[256];
  int cntA, cntB, rv;
  while (1) {
    cntA = read(a, bufA, 256);
    cntB = read(b, bufB, 256);
    if (cntA != cntB) {
      printf("Files differ\n");
      rv = 1; break;
    }
    if (memcmp(bufA, bufB, cntA)) {
      printf("Files differ\n");
      rv = 1; break;
    }
    if (cntA <= 0) {
      printf("Files are identical\n");
      rv = 0; break;
    }
  }
  close(a);
  close(b);
  return rv;
}