Read SPListItemVersion in SharePoint 2010

SPListItemVersion Class return the collection of versions for a list item. If versioning is enabled on a list, each time you modify an item a version is created.

Enable SharePoint List versioning using c#:

using (SPSite spsite = new SPSite("http://contoso.com"))
{
SPWeb spweb = spsite.OpenWeb();
SPList list = spweb.Lists["ListName"];
list.EnableVersioning = true;
list.Update();
}

Retrieve SPListItem versions using c#:

public  class PageVersions
 {
     public string PageVersion { get; set; }
     public SPUser PageVersionOwner { get; set; }
     public DateTime PageVersionDate { get; set; }
 }

public class GetVersionsClass
{

public  PageVersions CalculateVersionPoints(SPListItem item,int prevDates)
{
PageVersions pv = new PageVersions();

SPListItemVersionCollection oVersionInfo = item.Versions;

  foreach (SPListItemVersion oVersion in oVersionInfo)
  {
   if (oVersion.Level == SPFileLevel.Published)
   {



    if (oVersion.Created.ToLocalTime().CompareTo(DateTime.Now.AddDays(prevDates)) >= 0)
    {    
      pv.PageVersion = oVersion.VersionId.ToString();
      pv.PageVersionDate = oVersion.Created;
      pv.PageVersionOwner = oVersion.CreatedBy.User;
 
    }

   }
  }

  return pv;
}
}