Classes

SingleCharacterScript

using UnityEngine;
using System.Collections;

public class SingleCharacterScript : MonoBehaviour
{
    public class Stuff
    {
        public int bullets;
        public int grenades;
        public int rockets;
        
        public Stuff(int bul, int gre, int roc)
        {
            bullets = bul;
            grenades = gre;
            rockets = roc;
        }
    }
    
    
    public Stuff myStuff = new Stuff(10, 7, 25);
    public float speed;
    public float turnSpeed;
    public Rigidbody bulletPrefab;
    public Transform firePosition;
    public float bulletSpeed;
    
    
    void Update ()
    {
        Movement();
        Shoot();
    }
    
    
    void Movement ()
    {
        float forwardMovement = Input.GetAxis("Vertical") * speed * Time.deltaTime;
        float turnMovement = Input.GetAxis("Horizontal") * turnSpeed * Time.deltaTime;
        
        transform.Translate(Vector3.forward * forwardMovement);
        transform.Rotate(Vector3.up * turnMovement);
    }
    
    
    void Shoot ()
    {
        if(Input.GetButtonDown("Fire1") && myStuff.bullets > 0)
        {
            Rigidbody bulletInstance = Instantiate(bulletPrefab, firePosition.position, firePosition.rotation) as Rigidbody;
            bulletInstance.AddForce(firePosition.forward * bulletSpeed);
            myStuff.bullets--;
        }
    }
}

Inventory

using UnityEngine;
using System.Collections;

public class Inventory : MonoBehaviour
{
    public class Stuff
    {
        public int bullets;
        public int grenades;
        public int rockets;
        public float fuel;
        
        public Stuff(int bul, int gre, int roc)
        {
            bullets = bul;
            grenades = gre;
            rockets = roc;
        }
        
        public Stuff(int bul, float fu)
        {
            bullets = bul;
            fuel = fu;
        }
        
        // Constructor
        public Stuff ()
        {
            bullets = 1;
            grenades = 1;
            rockets = 1;
        }
    }
    

    // Creating an Instance (an Object) of the Stuff class
    public Stuff myStuff = new Stuff(50, 5, 5);
    
    public Stuff myOtherStuff = new Stuff(50, 1.5f);
    
    void Start()
    {
        Debug.Log(myStuff.bullets); 
    }
}

MovementControls

using UnityEngine;
using System.Collections;

public class MovementControls : MonoBehaviour
{
    public float speed;
    public float turnSpeed;
    
    
    void Update ()
    {
        Movement();
    }
    
    
    void Movement ()
    {
        float forwardMovement = Input.GetAxis("Vertical") * speed * Time.deltaTime;
        float turnMovement = Input.GetAxis("Horizontal") * turnSpeed * Time.deltaTime;
        
        transform.Translate(Vector3.forward * forwardMovement);
        transform.Rotate(Vector3.up * turnMovement);
    }
}

Shooting

using UnityEngine;
using System.Collections;

public class Shooting : MonoBehaviour
{
    public Rigidbody bulletPrefab;
    public Transform firePosition;
    public float bulletSpeed;
    
    
    private Inventory inventory;
    
    
    void Awake ()
    {
        inventory = GetComponent<Inventory>();
    }
    
    
    void Update ()
    {
        Shoot();
    }
    
    
    void Shoot ()
    {
        if(Input.GetButtonDown("Fire1") && inventory.myStuff.bullets > 0)
        {
            Rigidbody bulletInstance = Instantiate(bulletPrefab, firePosition.position, firePosition.rotation) as Rigidbody;
            bulletInstance.AddForce(firePosition.forward * bulletSpeed);
            inventory.myStuff.bullets--;
        }
    }
}