2D Sprite Rotation -- Help!

What aren't I declaring in the rotation part of the coding that I'm messing up with?

A friend sent me this and it comes up as "sprite" and "rotationset" do not exist in the current context, and I wasn't sure what to do.

Thanks!

using UnityEngine; using System.Collections;

public class MoveEnemy_A : MonoBehaviour {

 [HideInInspector]
 public GameObject[] waypoints_A;
 private int currentWaypoint = 0;
 private float lastWaypointSwitchTime;
 public float speed = 1.0f;

 void Start()
 {
     lastWaypointSwitchTime = Time.time;
 }


 void Update() {




     //1
     Vector3 startPosition = waypoints_A [currentWaypoint].transform.position;
     Vector3 endPosition = waypoints_A [currentWaypoint + 1].transform.position;
     //2
     float pathLength = Vector3.Distance (startPosition, endPosition);
     float totalTimeForPath = pathLength / speed;
     float currentTimeOnPath = Time.time - lastWaypointSwitchTime;
     gameObject.transform.position = Vector3.Lerp (startPosition, endPosition, currentTimeOnPath / totalTimeForPath);
     //3
     if (gameObject.transform.position.Equals (endPosition)) {
         if (currentWaypoint < waypoints_A.Length - 2) {
             // 3.a
             currentWaypoint++;
             lastWaypointSwitchTime = Time.time;

             RotateIntoMoveDirection();

         } else {
             //3.b
             Destroy(gameObject);
             //TODO: deduct health
         }
     }
 }



 // Rotate enemy sprite to match direction

 private void RotateIntoMoveDirection() {
     // TODO: smooth out rotation
     // Rotates sprite 90 degrees clockwise
     sprite.transform.Rotate(0,0,-90);
 }
 private void SouthRotate() {
     rotationset = false;
     // TODO: smooth out rotation
     // South - Set sprite starting rotation
     sprite.transform.rotation = Quaternion.Euler(0,0,0);
     // Rotation for this view has been set
     rotationset = true;
 }
 private void EastRotate() {
     rotationset = false;
     // TODO: smooth out rotation
     // East - Set sprite starting rotation
     sprite.transform.rotation = Quaternion.Euler(0,0,90);
     // Rotation for this view has been set
     rotationset = true;
 }
 private void NorthRotate() {
     rotationset = false;
     // TODO: smooth out rotation
     // North - Set sprite starting rotation
     sprite.transform.rotation = Quaternion.Euler(0,0,180);
     // Rotation for this view has been set
     rotationset = true;
 }
 private void WestRotate() {
     rotationset = false;
     // TODO: smooth out rotation
     // West - Set sprite starting rotation
     sprite.transform.rotation = Quaternion.Euler(0,0,270);
     // Rotation for this view has been set
     rotationset = true;
 }

}