[plt-scheme] suggestions and commendations for exercise 2.21

On Mar 29, 2004, at 11:38 AM, Terrence Brannon wrote:

> [2] I had problems trying to use convert-file because I wanted to use 
> a filename without specifying an absolute path, but did not know what 
> my current working directory was. I therefore did not know where to 
> place the input file or where to look for the output file.
>
> At what language level and with what procedure, does one find one's 
> current working directory?


I have modified convert-file so that it specifies where the file is 
expected:

> Welcome to DrScheme, version 206.1-cvs15mar2004.
> Language: Beginning Student.
> Teachpack: /Users/matthias/plt/teachpack/htdp/convert.ss.
> > (convert-file "in.dat" f "out.dat")
> convert-file: expected <name of existing file in 
> /Users/matthias/plt/collects/htdp/Test/> as first argument, given: 
> "in.dat"
> > (convert-file "convert-in.dat" f "out.dat")
...

Is this sufficiently helpful? -- Matthias