Reducing the value of an int/item stack

Questions & Answers
1

I am tweaking a build script for my survival game, and I want the player to only be allowed a set number of items to place. Here is the script allowing for infinite items:

using UnityEngine;
using System.Collections;

public class BuildScript : MonoBehaviour {
	
	RaycastHit hit;
	
	public Transform prefab;
	public Transform prefab2;

	// Use this for initialization
	void Start () {
	
	}
	
	// Update is called once per frame
	void Update () {
		
		Ray ray = camera.ViewportPointToRay(new Vector3(0.5F, 0.5F, 0));
		
		if(Physics.Raycast(ray, out hit)){
			
		if(Input.GetMouseButtonDown(1))
					Instantiate(prefab, hit.point, Quaternion.identity);
		
		if(Input.GetMouseButtonDown(0))
					Instantiate(prefab2, hit.point, Quaternion.identity);
		}
	
	}
}

Anyway, now it wont let me place anything at all:

using UnityEngine;
using System.Collections;

public class BuildScript : MonoBehaviour {

RaycastHit hit;

public Transform prefab;
public Transform prefab2;
public int pref;
public int pref2;

// Use this for initialization
void Start () {

}

// Update is called once per frame
void Update () {
	
	Ray ray = camera.ViewportPointToRay(new Vector3(0.5F, 0.5F, 0));
	
	if(Physics.Raycast(ray, out hit)){
		
	if(Input.GetMouseButtonDown(1))
			if(pref > 0)
				Instantiate(prefab, hit.point, Quaternion.identity);
				pref -= 1;
	
	if(Input.GetMouseButtonDown(0))
			if(pref2 > 0)
				Instantiate(prefab2, hit.point, Quaternion.identity);
				pref2 -= 1;
	}

}

}

2

void Update () {

    Ray ray = camera.ViewportPointToRay(new Vector3(0.5F, 0.5F, 0));

    if(Physics.Raycast(ray, out hit)){
       if(Input.GetMouseButtonDown(1)){
           if(pref > 0){
              Instantiate(prefab, hit.point, Quaternion.identity);
              pref -= 1;
           }
       }
       if(Input.GetMouseButtonDown(0)){
           if(pref2 > 0){
              Instantiate(prefab2, hit.point, Quaternion.identity);
              pref2 -= 1;
          }
       } 
   }
}