baner ad code of unity

 using System.Collections;

using System.Collections.Generic;

using UnityEngine;

using GoogleMobileAds;

using GoogleMobileAds.Api;

public class ads : MonoBehaviour

{

   public void Start()

    {

        // Initialize the Google Mobile Ads SDK.

        MobileAds.Initialize((InitializationStatus initStatus) =>

        {

            // This callback is called once the MobileAds SDK is initialized.

        });

        CreateBannerView();

    }

      // These ad units are configured to always serve test ads.

#if UNITY_ANDROID

  private string _adUnitId = "ca-app-pub-3940256099942544/6300978111";

#elif UNITY_IPHONE

  private string _adUnitId = "ca-app-pub-3940256099942544/2934735716";

#else

  private string _adUnitId = "unused";

#endif

  BannerView _bannerView;

  /// <summary>

  /// Creates a 320x50 banner at top of the screen.

  /// </summary>

  public void CreateBannerView()

  {

      Debug.Log("Creating banner view");

      // Create a 320x50 banner at top of the screen

      _bannerView = new BannerView(_adUnitId, AdSize.Banner, AdPosition.Top);

      LoadAd();

  }

  public void LoadAd()

{

    // create an instance of a banner view first.

    if(_bannerView == null)

    {

        CreateBannerView();

    }

    // create our request used to load the ad.

    var adRequest = new AdRequest();

    adRequest.Keywords.Add("unity-admob-sample");

    // send the request to load the ad.

    Debug.Log("Loading banner ad.");

    _bannerView.LoadAd(adRequest);

}

}