adventofcodeday1.c

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

#define MAX_STEPS 100

struct rotation {
  char direction;
  int steps;
  int location;
  int passwd;
};

void init(struct rotation *rotation) {
  rotation->direction = 0;
  rotation->steps = 0;
  rotation->location = 50;
  rotation->passwd = 0;
}

void format(int *location) {
  printf("Location before: %d\n", *location);
  *location = ((*location % MAX_STEPS) + MAX_STEPS) % MAX_STEPS;
  printf("Location after: %d\n", *location);
}

void rotate(struct rotation *rotation) {
  if (rotation->direction == 'R') {
    rotation->location += rotation->steps;
  } else {
    rotation->location -= rotation->steps;
  }
  format(&rotation->location);
  if (!rotation->location) {
    rotation->passwd++;
  }
}

int main() {
  struct rotation *rotation = malloc(sizeof(struct rotation));
  init(rotation);

  FILE *file = fopen("input", "r");
  if (file == NULL) {
    printf("Error opening file\n");
    return 1;
  }
  char *line = malloc(500);
  while (fgets(line, 500, file)) {
    sscanf(line, "%c%d", &rotation->direction, &rotation->steps);
    printf("Direction: %c, Steps: %d\n", rotation->direction, rotation->steps);
    rotate(rotation);
  }

  printf("Password is: %d\n", rotation->passwd);
  fclose(file);

  return 0;
}