Unexpected symbol 'return' in class, struct, or interface member declaration

it's important that you post the complete error message - it includes line number/character position of the error which will help us spot the problem and help you faster.

in this case, it looks like you've missed a comma on line 23. when you're copying tutorials, you need to be certain that you copy EVERYTHING ;)

hope that helps.

The book might be outdated but it's more like you didn't copy EVERYTHING in the RIGHT ORDER.

This part is all wrong:

  return Vector3.Distance(joueur.transform.position Transform.position);
  float getDistance(){
  }

The return line should be inside of the getDistance. And if you want to return a float, you have to give inputs. But I don't understand why you made a new return float that only uses Vector3.Distance which does the exact same thing as Vector3.Distance. Why not just use Vector3.Distance?

Fixed version:

  // Update is called once per frame
  void Update () {
      if (Vector3.Distance(joueur.transform.position Transform.position) < 5) {
          joueurVu = true;
          print ("Joueur Vu!");
      }
  
  }

Delete the return and getDistance lines. They aren't needed.

I took a code from an other source, but now I have a parsing error despite no accolade are missing. I searched for missing accolades, semicolons or bad syntax for a while, and I discovered that parsing error might be because of conflicted files (in any case what does it exactly mean) but the parsing error is still there. Here's my code:

 using UnityEngine;
 using System.Collections;
 
 public class IA : MonoBehaviour {
 
     bool joueurVu = false; //le joueur est-il repéré?
     public GameObject joueur; //le joueur
 
     // Use this for initialization
     void Start () {
         /*On recherche le joueur avec son nom et la fonction Find*/
         joueur = GameObject.Find("First Person Controller");
     
     }
 
     // Update is called once per frame
     void Update () {
         // If the player has been sighted and isn't dead...
         if(enemySight.personalLastSighting != lastPlayerSighting.resetPosition && playerHealth.health > 0f)
             // ... chase.
             Chasing();
         }
     
     }
 
     void using UnityEngine.Chasing;
 {
     // Create a vector from the enemy to the last sighting of the player.
     Vector3 sightingDeltaPos = enemySight.personalLastSighting - transform.position;
     
     // If the the last personal sighting of the player is not close...
     if(sightingDeltaPos.sqrMagnitude > 4f)
         // ... set the destination for the NavMeshAgent to the last personal sighting of the player.
         nav.destination = enemySight.personalLastSighting;
     
     // Set the appropriate speed for the NavMeshAgent.
     nav.speed = chaseSpeed;
     
     // If near the last personal sighting...
     if(nav.remainingDistance < nav.stoppingDistance)
     {
         // ... increment the timer.
         chaseTimer += Time.deltaTime;
         
         // If the timer exceeds the wait time...
         if(chaseTimer >= chaseWaitTime)
         {
             // ... reset last global sighting, the last personal sighting and the timer.
             lastPlayerSighting.position = lastPlayerSighting.resetPosition;
             enemySight.personalLastSighting = lastPlayerSighting.resetPosition;
             chaseTimer = 0f;
         }
     }
 }

Also, sometimes when i pass my mouse on the void before using UnityEngine.Chasing;, it tells me that this is an unexpected void, and sometimes it doesnt

https://gyazo.com/8647a97a68a3eea2b1bdd9ab31b1d5ec

https://gyazo.com/bafa1f641ced9cfeb56d75bcb60ea740