[racket] how must I interpreted this exercise

From: Roelof Wobben (r.wobben at home.nl)
Date: Sat Jun 23 14:45:01 EDT 2012

I have another "problem" I try to solve in my head.

Suppose I want to change one word in a sentence depening if a 
comparision is true or false.

I could do this in pseudo code.

if comparision is true then print "it's true" else  print "it's not true"

It works but I type two time's "it's true".

Can this be done so I have to type only one time the sentence and 
depeding on true or false the word not is used.


Op 23-6-2012 16:18, Matthias Felleisen schreef:
> Origin means (0,0) or plain 0 in English.
> On Jun 22, 2012, at 2:42 PM, Roelof Wobben wrote:
>> Hello,
>> I try to make this exercise :
>> Exercise 76: A programmer has chosen to represent locations as 
>> Cartesian points or just points:
>>     ;Location is one of:
>>     ;–Posn
>>     ;–Number
>>     ;interp. Posn are positions on the Cartesian grid,
>>     ;Numbers are positions on the number line
>> Design the function in-reach, which determines whether or not a given 
>> location’s distance to the origin is strictly less than some constantR.
>> So I must design a function called in-reach.
>> Am I right I need to use two structs (Posn) . One for the given 
>> location and one for the origon ?
>> Regards,
>> Roelof
>> ____________________
>>  Racket Users list:
>> http://lists.racket-lang.org/users

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