/*
    byte-counter.c
    Jeff Ondich, 9 Jan 2026

    Illustrates (barely) the use of command-line arguments and
    file input by opening the specified file, reading one byte
    at a time from the file, and reporting the total number of
    bytes.

    Simpler than byte-counter-better.c because this version
    ignores some important error states.
*/

#include <stdio.h>

void print_usage_statement(const char *program_name);

int main(int argc, char *argv[]) {
    // Parse the command line
    if (argc != 2) {
        print_usage_statement(argv[0]);
        return 1;
    }
    const char *input_file_name = argv[1];

    // Open the file
    FILE *input_file = fopen(input_file_name, "r");
    if (input_file == NULL) {
        fprintf(stderr, "Can't open %s for reading\n", input_file_name);
        return 1;
    }

    // Loop through the file one char/byte at a time, counting as we go.
    int count = 0;
    char ch = fgetc(input_file);
    while (ch != EOF) {
        count++;
        ch = fgetc(input_file);
    }
    fclose(input_file);

    // Print the results
    printf("Number of bytes in %s: %d\n", input_file_name, count);

    return 0;
}

void print_usage_statement(const char *program_name) {
    fprintf(stderr, "Usage: %s inputfile\n", program_name);
    fprintf(stderr, "  prints to standard output the number of bytes\n");
    fprintf(stderr, "  (as a decimal integer) in the specified file\n");
}