On Wed, Dec 22, 2010 at 11:54 AM, Sayth Renshaw <[email protected]>wrote:
> > > On Wed, Dec 22, 2010 at 11:39 AM, Sam Griff <[email protected]> wrote: > >> >> You need to start over and slow down because you are getting the basic >> Scheme syntax wrong. >> The gross pay function is already given: >> (define (wage h) >> (* 12 h)) >> >> You could modify it according to the previous suggestions to make it more >> readable: >> ; By convention constants are named in upper case >> (define TAX-RATE 0.15) >> (define PAY-RATE 12) >> >> (define (wage h) >> (* PAY-RATE h)) >> >> Where did your tax function go? How could you use tax and wage to develop >> netpay? >> >> Your attempt: >> >> (define (gross hours) >> (* hours pay-rate)) >> >> (define (netpay gross tax-rate) >> (-(gross)(* gross tax-rate))) >> >> Has a few major issues: 1) You have defined gross to take one argument but >> when you "call" it from (my 2nd point) you have provided no arguments and 2) >> you have named a "gross" parameter in netpay and use it twice. Which "gross" >> do you think is being used? The function or the passed value? >> >> Also: >> >> (define (netpay hours : number? tax : 0.85) >> (* hours 12)* tax) >> >> Where did you get that syntax from? Follow the examples in the book. >> Additionally, that is not even the right formula for computing netpay. >> Follow the development of functions for the exercise exactly and the proper >> formula should be clear. >> > > The main problem I am having is that I followed the examples in the book > without issue until I hit this example, something about it is throuwing me. > > To cover off Danny's post > > the error I am seeing is > > > f*unction call: expected a defined function name or a primitive operation > name after an open parenthesis, but found a function argument name* > > I will explain in numbers what i expect gross to do and maybe that will > make my operation clearer. I had defined gross as hours multiply pay rate. > > So pay rate in example was $12 and lets say I worked 20 hrs. my gross = 240 > > > (define (netpay gross tax-rate) > (-(gross)(* gross tax-rate))) > > So I expect the function to calculate as > > = (-(240)(* 240 0.15) > = ( - 240 36) > = 204 > > > >
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