animation switching

Unity Engine
1

I am trying to play another animation by accessing another animatorcontroller.How would i correct this script?

using UnityEngine;
using System.Collections;

public class ActivateAnimation : MonoBehaviour
{
    void OnCollisionEnter (Collision col)
    {
        if(col.gameObject.name == "prop_powerCube")
        {
            anim = GetComponent<Animator>();
          
          
            anim.runtimeAnimatorController = AnimationforPioyu ;
          
        }
    }
}
2

I don’t know much about animation, but from your script i can see that the variable anim is not declared but is used.
What is AnimationforPioyu ?
Also is good practice to not use GetComponent after initialization.

using UnityEngine;
using System.Collections;
public class ActivateAnimation : MonoBehaviour
{
    Animator anim;
  
     void Start()
        {
             anim=GetComponent<Animator>();
        }

    void OnCollisionEnter (Collision col)
    {
        if(col.gameObject.name == "prop_powerCube")
        {
      
      
            anim.runtimeAnimatorController = AnimationforPioyu ; 
      
        }
    }
}
3

AnimationforPioyu is a animatorcontroller.