5.6 tp

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#define ARG_ERROR "WRONG NR. OF ARGS!\n"
#define EVER ;;

FILE *openFile(const char path[], const char mode[]) {
  FILE *file = fopen(path, mode);
  if (file == NULL) {
    perror("");
    exit(EXIT_FAILURE);
  }
  return file;
}

void closeFile(FILE *file) {
  if (fclose(file) == EOF) {
    perror("");
  }
}

int main(int argc, char *argv[]) {
  if (argc < 3) {
    fprintf(stderr, ARG_ERROR);
    exit(-1);
  }

  FILE *file1 = openFile(argv[1], "rb");
  FILE *file2 = openFile(argv[2], "rb");

  uint8_t byte1, byte2;
  for (EVER) {
    fread(&byte1, sizeof(uint8_t), 1, file1);
    fread(&byte2, sizeof(uint8_t), 1, file2);
    if (byte1 != byte2) {
      const long offset = ftell(file1);
      printf("%08ld: %02x %02x\n", offset, byte1, byte2);
    }
    if (byte1 == 0xA) {
      fread(&byte1, sizeof(uint8_t), 1, file1);
      break;
    }
    if (byte2 == 0xA) {
      fread(&byte2, sizeof(uint8_t), 1, file2);
      break;
    }
  }

  while (fread(&byte1, sizeof(uint8_t), 1, file1)) {
    const long offset = ftell(file1);
    printf("%08ld: %02x   \n", offset, byte1);
  }
  while (fread(&byte2, sizeof(uint8_t), 1, file2)) {
    const long offset = ftell(file2);
    printf("%08ld:    %02x\n", offset, byte2);
  }//*/

  closeFile(file1);
  closeFile(file2);
  return 0;
}