Access parts of different scripts?

I need to access a script within another script, but I can’t figure out how.
I have a simple script that displays the current round, like so

using UnityEngine;
using System.Collections;

public class GUITextHandler : MonoBehaviour
{
   public GameObject gui;
    static int score;

    void update()
    {

        gui.GetComponent ("GUIText").text = "Score: " + score;

    }
}

this is supposed to change the GUIText component to whatever I set it to.

then I have another script that launches a function called “WaveEnded” whenever the wave ends.

what do I put in the “WaveEnded” function to make it so whenever the wave ends, the “score” goes up by 1?

Thanks very much for your time

static int score;
Change that to

public static int score;

To be able to access it from WaveEnded:

void WaveEnded()
{
     GUITextHandler.score++;
}