i have this code

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

#define NUM_CLIENTS 5
#define DB_SIZE 500
#define DATA_SIZE 1024
#define BANDWIDTH 10000
#define CACHE_SIZE 100
#define HOT_DATA_ITEMS 50
#define HOT_DATA_ACCESS_PROB 0.8
#define COLD_DATA_ITEMS (DB_SIZE - HOT_DATA_ITEMS)
#define HOT_DATA_UPDATE_PROB 0.33

int query_count = 0, hit_count = 0, cold_count = 0, update_count = 0;
double query_delay = 0;

int cache[CACHE_SIZE]; // array to store cached data items
int hot_data[HOT_DATA_ITEMS]; // array to store hot data items
int cold_data[COLD_DATA_ITEMS]; // array to store cold data items

double T_QUERY = 5; // mean query generation time
double T_UPDATE = 5; // mean update arrival time

void init_data() {
int i;
// initialize cache with -1 to indicate empty slots
for (i = 0; i < CACHE_SIZE; i++) {
cache[i] = -1;
}
// initialize hot data items and cold data items
for (i = 0; i < HOT_DATA_ITEMS; i++) {
hot_data[i] = rand() % DB_SIZE; // generate random hot data item id
cold_data[i] = -1; // initialize cold data item with -1
}
for (i = 0; i < COLD_DATA_ITEMS; i++) {
cold_data[i] = rand() % DB_SIZE; // generate random cold data item id
}
}

int is_in_cache(int data_id) {
int i;
// check if data item is in cache
for (i = 0; i < CACHE_SIZE; i++) {
if (cache[i] == data_id) {
return 1; // data item is in cache
}
}
return 0; // data item is not in cache
}

void update_cache(int data_id) {
int i, lru_index = 0, lru_time = simtime() + 1;
// update cache with new data item
for (i = 0; i < CACHE_SIZE; i++) {
if (cache[i] == data_id) {
return; // data item is already in cache, no need to update
}
if (cache[i] == -1) {
cache[i] = data_id; // found empty slot, update with new data item
return;
}
if (lastchange(cache[i]) < lru_time) {
lru_index = i; // found least recently used slot
lru_time = lastchange(cache[i]);
}
}
cache[lru_index] = data_id; // update least recently used slot with new data item
}

int find_data(int data_id) {
int i;
// check if data item is a hot data item
for (i = 0; i < HOT_DATA_ITEMS; i++) {
if (hot_data[i] == data_id) {
return HOT_DATA_ACCESS_PROB >= ((double) rand() / RAND_MAX); // check if hot data item is accessed
}
}
// check if data item is a cold data item
for (i = 0; i < COLD_DATA_ITEMS; i++) {
if (cold_data[i] == data_id) {
return 1; // data item is a cold data item and is available
}
}
cold_count++; // data item is not in database, counted as cold data access
return 0; // data item is not available
}

double generate_query() {
int data_id = rand() % DB_SIZE; // generate random data item id
if (is_in_cache(data_id)) {
query_count++;
wait(0.001); // wait for a small amount of time to simulate cache hit
return 0;
}
wait(expntl(1.0/T_QUERY)); // wait for mean query generation time to simulate cache miss
if (find_data(data_id)) {
hit_count++; // data item found, counted as cache hit
update_cache(data_id); // update cache with new data item
}
query_count++;
return simtime() - event_time; // calculate query delay
}

void generate_update(int data_id) {
if (HOT_DATA_UPDATE_PROB >= ((double) rand() / RAND_MAX)) {
hot_data[rand() % HOT_DATA_ITEMS] = data_id; // update a random hot data item
} else {
cold_data[rand() % COLD_DATA_ITEMS] = data_id; // update a random cold data item
}
update_count++;
}

void server() {
int data_id = rand() % DB_SIZE; // generate random data item id
generate_update(data_id); // update database with new data item
write("Data updated: ");
writeline(data_id);
hold(expntl(1.0/T_UPDATE)); // wait for mean update arrival time
}

void client() {
while (1) {
generate_query(); // generate queries continuously
}
}

int main() {
init_data(); // initialize data
T_QUERY = 5; // set mean query generation time
T_UPDATE = 5; // set mean update arrival time
set_seed(12345);
start_simulation(); // start CSIM simulation
process(“main”); // create main process
int i;
for (i = 0; i < NUM_CLIENTS; i++) {
process(client); // create client processes
}
process(server); // create server process
hold(10000.0); // wait for simulation to finish
printf(“Total queries: %d, hits: %d, hit rate: %.2f%%\n”,
query_count, hit_count, (double) hit_count / query_count * 100);
printf(“Cold data queries: %d, update count: %d\n”, cold_count, update_count);
return 0;
}