Array data-handling with NPC class

1. C++ is statically typed programming language. Due to this overhead for allocation of class members is very small.

2. Using of global variables is not a good idea. Such vars like NUM_NPC makes your application non-scalable.

3. Each domain object (like a player or an item) must be described by a same-named class.

#include <iostream>
#include <string>
#include <vector>

typedef int Hearts;
typedef bool Gender;

struct Date
{
      Date(int month,int day) : month(month), day(day) {}
      int month;
      int day;
};

class Item
{
    // TODO: implement
};

class Player
{
public:
      Player(std::string name, Hearts hearts, Date birthday, Gender gender)
            : name(name), hearts(hearts), birthday(birthday), gender(gender) {}

      Hearts getHearts() const
      {
            return hearts;
      }

      const std::vector<Item>& getItems()
      {
            return items;
      }

      Date getBirthday() const
      {
            return birthday;
      }

      std::string getName() const
      {
            return name;
      }
private:
      std::vector<Item> items;
      Hearts hearts;
      Date birthday;
      std::string name;
      Gender gender;
};

int main()
{
      using namespace std;

      vector<Player> players;
      players.push_back(Player("Ace", 0, Date(3,5), 0));
      players.push_back(Player("Amber", 0, Date(9,20), 1));
      players.push_back(Player("Benny", 0, Date(1,10), 0));
      players.push_back(Player("Ethan", 0, Date(12,30), 0));

      Player& p = players[1];
      cout << "Player 1 Details:" << endl;
      cout << "Name: " << p.getName() << endl;
      cout << "Hearts: " << p.getHearts() << endl;
      cout << "Birthday: " << p.getBirthday().month << "/" << p.getBirthday().day << endl;
      cout << "Item count: " << p.getItems().size() << endl;
}

There's little need for macros (#defines) in C++, unlike in C:

#define NUM_NPC 10       // Number of NPC players

#define DETAILS_HEARTS 0 // Heart Position
#define DETAILS_BDMON  1 // Birthday Month Position
#define DETAILS_BDDAY  2 // Birthday Day Position
#define DETAILS_GENDER 3 // NPC Gender

The first macro should instead be a constant, using the const keyword:

const int NUM_NPC = 10;

The rest of them can be put into an enum:

enum Detail { HEARTS, BDMON, BDDAY, GENDER };

Each respective value inside still ranges from 0 to 3.

Inside the class, you're using accessors ("getters"), which is bad for encapsulation. Plus, you're only displaying them in the calling code, so you don't even need the values themselves.

Not only that, but you're not constructing the npcPlayers object correctly. You're invoking its default constructor, then passing something to each accessor (which appears to be playerID).

Here's now the object should be constructed:

npcPlayers nps(1);

In your class definition, the constructor should be overloaded as such:

npcPlayers(int playerID) : playerID(playerID) {}

In order for that to work, you must first add playerID as a new private member.

Finally, create a new public display() member function:

void npcPlayers::display() const
{
    std::cout << "Player 1 Details:\n";
    std::cout << "Name: " << npcNames[playerID] << "\n";
    std::cout << "Hearts: " << npcDetails[playerID][DETAILS_HEARTS] << "\n";
    std::cout << "Birthday: " << npcDetails[playerID][DETAILS_BDMON]
        << "/" << npcDetails[playerID][DETAILS_BDDAY] << "\n";
}

With this, you can simply display all of this in the calling code as such:

npc.display();

Misc.:

• Try not to use using namespace std.
• There's no need to use C-strings in C++. Instead, use std::string objects.
• You don't need return 0 at the end of main(). As successful termination is always implied at this point, the compiler will insert this return for you automatically.