Find first and last day of specific months before/after current date using SQL server

My today's blog post is about finding the first and last day of any month from the current day. Today while working on a report project user needed details from last six month to next six months. So I created this query.

DECLARE @FirstDay DATETIME ,

    @LastDay DATETIME ,

    @MonthBackward INT = 6 ,

    @MonthForward INT = 6;

-- First Day of Month which was before @monthbackward

SET @FirstDay = ( SELECT    DATEADD(MONTH,

                                    DATEDIFF(MONTH, 0,

                                             DATEADD(MONTH, -@MonthBackward,

                                                     GETDATE())), 0)

                );

-- Last Day of Month which was after @

SET @LastDay = ( SELECT DATEADD(MONTH, 1,

                                DATEADD(MONTH, @MonthForward, GETDATE())

                                - DAY(DATEADD(MONTH, @MonthForward, GETDATE()))

                                + 1) - 1

               ); 

SELECT  @FirstDay [Day_1_SixMonthBefore] ,

        @LastDay [Day_last_SixMonthAfter];