Cannot Check Cluster Index Sql Server I am just check if my table has Cluster Index or not by running this query

Table Design

CREATE TABLE [dbo].[postTB](
[postID] [bigint] IDENTITY(1,1) NOT NULL,
[slug] [nvarchar](300) NULL,
[title] [varchar](150) NOT NULL,
[postContent] [nvarchar](max) NULL,
[createDate] [datetime] NULL,
[publishDate] [datetime] NULL,
[userID] [bigint] NOT NULL,
[categoryID] [bigint] NOT NULL,
[isShow] [bit] NOT NULL,
[isApproved] [bit] NULL,
[websiteID] [int] NULL,
[miniPostContent] [nvarchar](300) NULL,
[modifedDate] [datetime] NULL,
[pageTitle] [nvarchar](300) NULL,
[pageKeyword] [nvarchar](300) NULL,
[pageDescribtion] [nvarchar](300) NULL,
[CombinedTags] [nvarchar](300) NULL,
[blogImage] [nvarchar](50) NULL,
[postBlogType] [nvarchar](50) NULL,
[postTag] [nvarchar](100) NULL,
[firstname] [nvarchar](50) NULL,
[lastname] [nvarchar](50) NULL,
[contactemail] [nvarchar](50) NULL,
[viewcount] [bigint] NULL CONSTRAINT [DF_postTB_viewcount_1]  DEFAULT ((1)),
[blogCategoryTypeID] [int] NULL CONSTRAINT [DF_postTB_blogCategoryTypeID]  DEFAULT ((0)),
CONSTRAINT [PK_postTB] PRIMARY KEY CLUSTERED 
(
[postID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, 
 ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]


I am executing this


  Execute sp_helpindex [postTB]


But the result is


  The object 'postTB' does not exist in database 'cwpros' or is invalid for this operation.


Please help how to properly create cluster if not exist then check using above command?
Your script is correct, and if you get the error 


  The object 'postTB' does not exist in database 'cwpros' or is invalid
  for this operation.


this means some of the following: 


you created your table in other db than cwpros
someone dropped your table
your default schema is not dbo and you have anothe object with the
same name in your schema, but it's not a table


So first of all make sure that the object does exist in your database:

select *
from sys.objects
where name = 'postTB'