State AA simulator.

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

#define MAX_TRIALS 1024

typedef struct {
  double aa_level;
  double aa_dmg_tech;
  double aa_radar_tech;

  int planes;
  int air_defence;

  int planes_killed;
  double total_c;
} stats_t;

int simulate_aa(stats_t *stats, double rfactor);

int main(const int argc, const char **argv) {

  if (argc < 6)
    exit(-1);

  srand(time(NULL));

  register stats_t *stats = malloc(sizeof(stats_t));
  stats->aa_level      = atof(argv[1]) / 5;
  stats->aa_dmg_tech   = 1 + 0.1 * atoi(argv[2]);
  stats->aa_radar_tech = 1 + 0.2 * atoi(argv[3]);
  stats->total_c = 0.1 * stats->aa_radar_tech * stats->aa_level;

  int total_sim_kc = 0;

  for (int i = 0; i < MAX_TRIALS; ++i) {

    stats->planes        = atoi(argv[4]);
    stats->air_defence   = atoi(argv[5]);
    stats->planes_killed = 0;

    int plane_attacks = 0;
    int aa_attacks = 0;

    while (plane_attacks < 90 && stats->planes > 0) { // modifiable trial condition.
      printf("Day %d, %d:00 | Total kills: %d.\n", plane_attacks / 3, plane_attacks % 3 * 8, stats->planes_killed);
      ++plane_attacks;
      double rfactor = (double) (rand() % 1001) / 1000;
      if (rfactor < stats->total_c) {
        ++aa_attacks;
        // simulate_aa(stats, rfactor);
        printf("Day %d, %d:00 | Shot down %d planes.\n", plane_attacks / 3, plane_attacks % 3 * 8, simulate_aa(stats, rfactor));
      }
    }

    total_sim_kc += stats->planes_killed;
  }

  printf("Finished.  Mean kills: %d\n\n", total_sim_kc / MAX_TRIALS);
  free(stats);
  return 0;
}

int simulate_aa(stats_t *stats, double rfactor) {

  double aa_kills = (0.8 * rfactor * stats->aa_level * stats->planes * stats->aa_dmg_tech)/(stats->air_defence * stats->total_c);
  int kills = aa_kills >= 1 ? round(aa_kills) : 1;
  stats->planes_killed += kills;
  stats->planes -= kills;
  return kills;
}