Interstantial ads script

using System.Collections;

using System.Collections.Generic;

using UnityEngine;

using GoogleMobileAds;

using GoogleMobileAds.Api;

public class interstatial : MonoBehaviour

{

  public void Start()

    {

        // Initialize the Google Mobile Ads SDK.

        MobileAds.Initialize((InitializationStatus initStatus) =>

        {

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

        });

        LoadInterstitialAd();

    }

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

#if UNITY_ANDROID

  private string _adUnitId = "ca-app-pub-3940256099942544/1033173712";

#elif UNITY_IPHONE

  private string _adUnitId = "ca-app-pub-3940256099942544/4411468910";

#else

  private string _adUnitId = "unused";

#endif

  private InterstitialAd interstitialAd;

  /// <summary>

  /// Loads the interstitial ad.

  /// </summary>

  public void LoadInterstitialAd()

  {

      // Clean up the old ad before loading a new one.

      if (interstitialAd != null)

      {

            interstitialAd.Destroy();

            interstitialAd = null;

      }

      Debug.Log("Loading the interstitial ad.");

      // 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.

      InterstitialAd.Load(_adUnitId, adRequest,

          (InterstitialAd ad, LoadAdError error) =>

          {

              // if error is not null, the load request failed.

              if (error != null || ad == null)

              {

                  Debug.LogError("interstitial ad failed to load an ad " +

                                 "with error : " + error);

                  return;

              }

              Debug.Log("Interstitial ad loaded with response : "

                        + ad.GetResponseInfo());

              interstitialAd = ad;

          });

          ShowAd();

  }

  /// <summary>

/// Shows the interstitial ad.

/// </summary>

public void ShowAd()

{

    if (interstitialAd != null && interstitialAd.CanShowAd())

    {

        Debug.Log("Showing interstitial ad.");

        interstitialAd.Show();

    }

    else

    {

        Debug.LogError("Interstitial ad is not ready yet.");

    }

}

}