Hash C

struct Nod {
  int info, freq;
  Nod *next;
} *Hash[MOD];

void Add (int x) {
  int key = x % MOD;
  Nod *node = new Nod;
  node -> info = x;
  node -> freq = 1;
  node -> next = Hash[key];
  Hash[key] = node;
}

void Insert (int x) {
  int key = x % MOD;
  Nod *node = Hash[key];
  while (node && node -> info != x)
    node = node -> next;
  if (!node)
    Add (x);
  else
    node -> freq ++;
}

void Erase (int x) {
  int key = x % MOD;
  Nod *node = Hash[key];
  while (node && node -> info != x)
    node = node -> next;
  if (node != nullptr && node -> freq > 0)
    node -> freq --;
}

int Find (int x) {
  int key = x % MOD;
  Nod *node = Hash[key];
  while (node != nullptr && node -> info != x)
    node = node -> next;
  if (node == nullptr)
    return 0;
  else
    return node -> freq;
}