Advent of code d1

I never manage to finish advent of code. Here is my C solution to day 1.

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

#define MAX_LINE_LENGTH 99

int main() {
    int result = 50;
    int password = 0;
    FILE *f;

    char line[MAX_LINE_LENGTH];
    const char *filename = "day1-input.txt";
    f = fopen(filename, "r");
    if(f == NULL) {
        perror("error opening");
        return 1;
    }
    while(fgets(line, MAX_LINE_LENGTH, f) != NULL) {
        size_t len = strlen(line);
        if(len > 1 && (line[0] == 'L' || line[0] == 'R')) {
            int n = atoi(line + 1);
            for(int i = 0; i < n; i++) {
                if(line[0] == 'L') {
                    result--;
                    if(result < 0) result = 99;
                } else {
                    result++;
                    if(result > 99) result = 0;
                }
                // increment here for second phase
                // if(result == 0) password++;
            }
            // increment here for first phase
            if(result == 0) password++;
        }
    }
    fclose(f);

    printf("%d\n", password);
    return 0;
}