Convert SQL function into RPG (or C) language

Project Description:
There's a SQL function that needs to be translated into RPG (or C) language.
All the functionality in translated function has to be exactly as in the original. In the bidding, please mention the language you'll use for the outcome (RPG or C).
Below please review the original SQL function.

Thank you!

drop function dbo.PMT
go
create function dbo.PMT
(
-- Datetype for @rate changed to float
@rate float,
@periods smallint,
@principal numeric(20,2)
)
returns numeric (38,9)
as
begin
declare @pmt numeric (38,9)

declare @WK_periods float,
@WK_principal float,
@wk_One float,
@WK_power float

-- Convert data for calculation
select @WK_periods = @periods,
@WK_principal = @principal,
@WK_One = 1

select @pmt =
round(
-- Do all multiplication before division
( @WK_principal * (@rate*power(@WK_One+@rate,@WK_periods)))
/ (power(@WK_One+@rate,@WK_periods)-@WK_One)
,9)

return @pmt

end