#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
#define NOPOSITION (-1)

int main(int argc, char* argv[]) {
    if (argc != 2 && argc != 4) {
        fprintf(stderr, "Usage:  %s <filename> [--from POSITION]\n", argv[0]);
        return EXIT_FAILURE;
    }
    int from_position = NOPOSITION;  // means didn't get --from
    if(argc == 4 && strcmp(argv[2], "--from") == 0) {
        from_position = atoi(argv[3]);
    }

    char* filename = argv[1];
    FILE* fp = fopen(filename, "r"); // Will return NULL if doesn't exist
    if(from_position != NOPOSITION) {
        fseek(fp, from_position, SEEK_SET);  // TODO:  WHAT DO YOU PUT IN HERE?
    };

    int num_chars = 0;
    while(true) {
        int ch = fgetc(fp);
        if(ch == EOF) {
            break;
        }
        fputc(ch, stdout);
        num_chars += 1;
    };

    int current_position = ftell(fp);   // USE ftell(..) to find the
    // location when we got to the end.
    int num_chars_efficient = current_position - from_position;
    printf("\n%d characters\n", num_chars);
    printf("\n%d characters\n", num_chars_efficient);
    return EXIT_SUCCESS;
}
/* vim: set tabstop=4 shiftwidth=4 fileencoding=utf-8 noexpandtab: */
/* vim: set tabstop=4 shiftwidth=4 fileencoding=utf8: */