Camera Zoom Input change.

Hello

I found this script on the forums, which is just what i need.
But i need it to use the mouse scrollwheel. This being in C# i have no idea how to do it.
Any help would be appreciated.

using UnityEngine;

using System.Collections;

 

public class CameraZoom : MonoBehaviour {

    public int zoomLevelSelected;

    public float altFieldOfView = 60.0f;

    public float ZoomLevel = 60.0f; 

    public float ZoomLevel1 = 40.0f;

    public float ZoomLevel2 = 20.0f;

    // Use this for initialization

    void Start () {

        zoomLevelSelected = 0;

        

    }

 

    // Update is called once per frame

    void Update () {

    

    if(Input.GetMouseButtonDown(1) || Input.GetKeyDown(KeyCode.Plus) || Input.GetKeyDown(KeyCode.Minus))

    {

        if(Input.GetKeyDown(KeyCode.Minus))

             zoomLevelSelected -= 1;

        else

             zoomLevelSelected += 1;

 

        float temp = camera.fieldOfView;

 

        if(zoomLevelSelected > 2)

            {

                zoomLevelSelected = 0;

            }

        switch(zoomLevelSelected)

        {

                

            case 0:

                

                camera.fieldOfView = ZoomLevel;

                ZoomLevel = temp;

                print (zoomLevelSelected);

                break;

            case 1:

                

                camera.fieldOfView = ZoomLevel1;

                ZoomLevel1 = temp;

                print (zoomLevelSelected);

                break;

            case 2:

                

                camera.fieldOfView = ZoomLevel2;

                ZoomLevel2 = temp;

                print (zoomLevelSelected);

                break;

 

            

        }

        }

    

}

}
using UnityEngine;
using System.Collections;
public class CameraZoom : MonoBehaviour
{
	public int zoomLevelSelected;
	public float altFieldOfView = 60.0f;
	public float ZoomLevel = 60.0f;
	public float ZoomLevel1 = 40.0f;
	public float ZoomLevel2 = 20.0f;
	// Use this for initialization
	void Start()
	{
		zoomLevelSelected = 0;
	}

	// Update is called once per frame
	void Update()
	{
		int zoomChange = 0;
		if (Input.GetAxis("Mouse ScrollWheel") < 0) { zoomChange = +1; } // back
		else if (Input.GetAxis("Mouse ScrollWheel") > 0) { zoomChange = -1; } // forward

		if (zoomChange!=0)
		{
			zoomLevelSelected = Mathf.Clamp(zoomLevelSelected + zoomChange, 0, 2);
			float temp = camera.fieldOfView;
			switch (zoomLevelSelected)
			{
				case 0:
					camera.fieldOfView = ZoomLevel;
					ZoomLevel = temp;
					print(zoomLevelSelected);
					break;
				case 1:
					camera.fieldOfView = ZoomLevel1;
					ZoomLevel1 = temp;
					print(zoomLevelSelected);
					break;
				case 2:
					camera.fieldOfView = ZoomLevel2;
					ZoomLevel2 = temp;
					print(zoomLevelSelected);
					break;
			}
		}
	}
}

bonus: i like this one much ore 8) (just little improvements)

using UnityEngine;
using System.Collections;
public class CameraZoom : MonoBehaviour
{
	public int zoomLevelSelected = 0;
	public float[] ZoomLevels = new float[] { 60, 40, 20 };
	void Update()
	{
		int zoomChange = 0;
		if (Input.GetAxis("Mouse ScrollWheel") < 0) { zoomChange = +1; } // back
		else if (Input.GetAxis("Mouse ScrollWheel") > 0) { zoomChange = -1; } // forward
		if (zoomChange != 0)
		{
			zoomLevelSelected = Mathf.Clamp(zoomLevelSelected + zoomChange, 0, ZoomLevels.Length - 1);
			camera.fieldOfView = ZoomLevels[zoomLevelSelected];
		}
	}
}