Unity script to move a player

MovePlayers.cs

using UnityEngine;
using System.Collections;

public class MovePlayer : MonoBehaviour {

  private bool d_positive = true;
  private float x = 0.05f;
  private float x_sum = 0.0f;
  private float x_max = 2.0f;
	// Use this for initialization
	void Start () {
	
	}
	
	// Update is called once per frame
	void Update () {

    if (d_positive && Mathf.Abs(x_sum) < x_max) { // Move positive direction
      transform.localPosition = new Vector3(x_sum, 0, 0);
      x_sum += x;
    } else if (!d_positive && Mathf.Abs(x_sum) < x_max) { // Move negative direction
      transform.localPosition = new Vector3(x_sum, 0, 0);
      x_sum -= x;
    } else {

      if(d_positive){
        x_sum -= x;
      } else {
        x_sum += x;
      }
      d_positive = !d_positive;

    }
          
	}
}