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

#define MAX_LINE_LENGTH 500 

int count_lines(FILE *file);

int main(int argc, char **argv) {
    if (argc != 2) {
        fprintf(stderr, "usage: ./line_count FILE\n");
        return 1; 
    }

    FILE *file = fopen(argv[1], "r"); 
    if (file != NULL) { 
        int lines = count_lines(file);
        if (lines == -1) {
            fprintf(stderr, "");
            return 3;
        }
        printf("%d\n", lines); 
        return 0; 
    } else {
        fprintf(stderr, "line_count: error opening %s\n", argv[1]);
        return 2;
    }
}

int count_lines(FILE *file) {
    int count = 0;
    char line[MAX_LINE_LENGTH]; 
    while(fgets(line, MAX_LINE_LENGTH, file)) {
        count++;
    }
    if (ferror(file)) {
        return -1;
    }
    return count;
}