Health Damage and Health Bar Code

public class HealthBar : MonoBehaviour
{
 //  player's health and health bar
 public float curHP=100;
 public float maxHP=100;
 public float maxBAR=100;
 public float HealthBarLength;


 void OnGUI()
 {
  //  creates the health bar at the coordinates 10,10
  GUI.Box(new Rect(10,10,HealthBarLength,25), "");
  //  determines the length of the health bar
  HealthBarLength=curHP*maxBAR/maxHP;
 }

 void ChangeHP(float Change)
 {
  //  takes whatever value is passed to this function and add it to curHP.
  curHP+=Change;

  // This if statement ensures we don't go over the max health
  if(curHP>maxHP)
  {
   curHP=100;
  }

  // This if statement is to check if the player has died
  if(curHP<=0)
  {
   // Die
   Debug.Log("Player has died!");
  }
 }

 // This function checks if the player has entered a trigger
 void OnTriggerEnter(Collider other)
 {
  // The switch statement checks what tag the other gameobject is, and reacts accordingly.
  switch(other.gameObject.tag)
  {
  case "Heal":
   ChangeHP(5);
   break;
  case "Damage":
   ChangeHP(-25);
   break;
  }
  // Finally, this line destroys the gameObject the player collided with.
  Destroy(other.gameObject);
 }
}


Now we just need to add a timer which Alice is currently looking into :)

using UnityEngine;
using System.Collections;
public class HealthBar : MonoBehaviour
{
 //  player's health and health bar
 public float curHP=100;
 public float maxHP=100;
 public float maxBAR=100;
 public float HealthBarLength;
 private float updateDisplayTime = 0F;


 void Start()
 {
   updateDisplayTime = Time.time + 5F;
 }

 void Update()
 {

        if ( updateDisplayTime < Time.time )
     
   {
         curHP -= 3;
         updateDisplayTime = Time.time + 5F;
   }

    if ( curHP <= 0 )
      {
          this.enabled = false;
      }
 }
 void OnGUI()
 {
  //  creates the health bar at the coordinates 10,10
  GUI.Box(new Rect(10,10,HealthBarLength,25), "");
  //  determines the length of the health bar
  HealthBarLength=curHP*maxBAR/maxHP;
 }

 void ChangeHP(float Change)
 {
  //  takes whatever value is passed to this function and add it to curHP.
  curHP+=Change;

  // This if statement ensures we don't go over the max health
  if(curHP>maxHP)
  {
   curHP=100;
  }

  // This if statement is to check if the player has died
  if(curHP<=0)
  {
   // Die
   Debug.Log("Player has died!");
  }
 }

 // This function checks if the player has entered a trigger
 void OnTriggerEnter(Collider other)
 {
  // The switch statement checks what tag the other gameobject is, and reacts accordingly.
  switch(other.gameObject.tag)
  {

  case "Heal":
   ChangeHP(5);
   break;
  case "Damage":
   ChangeHP(-1);
   break;

   if ( updateDisplayTime < Time.time )
    
  {
        curHP -= 10;
        updateDisplayTime = Time.time + 5F;
  }

   if ( curHP <= 0 )
     {
         this.enabled = false;
     }

  }
  // Finally, this line destroys the gameObject the player collided with.
  Destroy(other.gameObject);
 }
}

The "private float updateDisplayTime = 0F;" we managed to find from one of Alisters lessons, so that there is a counter to how quickly the health decreases when you're near the trees.