Creating a SharePoint list Programmatically using xml field definitions.

private static Guid createList(string listName, SPWeb web)
{
      Guid ListId = web.Lists.Add(listName, "Description here", SPListTemplateType.GenericList);
      SPList list= web.Lists.GetList(ListId, false);
      if (list!= null)
      {
          list.Fields.AddFieldAsXml("<field displayname='Field1' enforceuniquevalues='FALSE' indexed='FALSE' required='TRUE' type='Text'>", true, SPAddFieldOptions.AddFieldToDefaultView);
          list.Fields.AddFieldAsXml("<field displayname='Field2' enforceuniquevalues='FALSE' indexed='FALSE' required='FALSE' type='Text'>", true, SPAddFieldOptions.AddFieldToDefaultView);
          list.Fields.AddFieldAsXml("<field displayname='Field3' enforceuniquevalues='FALSE' indexed='FALSE' required='FALSE' type='Text'>", true, SPAddFieldOptions.AddFieldToDefaultView);
          list.Fields.AddFieldAsXml("<field displayname='Field4' enforceuniquevalues='FALSE' indexed='FALSE' required='FALSE' type='Text'>", true, SPAddFieldOptions.AddFieldToDefaultView);

          list.Update();
      }
      return ListId;
}