Anyone familiar with Scheme programming?

[hans030390]

I'm in an intro to computer science class, and there's one problem I can't quite figure out. I have to create a procedure, "pick-one-at-random" that will select one of two given arguments randomly (with equal probibility).

Examples:

> (pick-one-at-random 1 -1)
1
> (pick-one-at-random #t #f)
#f
> (pick-one-at-random #t 64)
#t
> ((pick-one-at-random + -) 3 4)
7
> (pick-one-at-random
(pick-one-at-random 1 2)
(pick-one-at-random 3 4))
4

My professor said to "think of it as flipping a coin, and one coin only" and that we only need to use "if" once in our code.

Can anyone provide and help or hints?

 

[esun]

You need a way to generate a random number. Luckily, Scheme provides this:

http://groups.csail.mit.edu/ma...on/scheme_5.html#SEC61

For example, (random 2) would give you a 0 with probability 0.5 and a 1 with probability 0.5. I think you should be able to figure out the rest.

EDIT: Fixed the code.

 

[hans030390]

I don't see how this answers or helps my problem. I give it two arguments, and it simply picks between one of them. Random picks a random number below the given argument.

I just learned that I need to have to "random"s in my code...one if...I suppose that helps a bit...any ideas?

 

[hans030390]

Nevermind, I figured it out via help from someone else. Thanks, though.

 

[IHateMyJob2004]

Scheme is a very good OO language. EMBRACE IT!!!!

You will elarn concepts via Scheme more so than most other languages (Java included)

 

[tfinch2]

Originally posted by: IHateMyJob2004
Scheme is a very good OO language. EMBRACE IT!!!!

You will elarn concepts via Scheme more so than most other languages (Java included)

Scheme is a functional language...

 

[esun]

Not entirely. Like most other languages, Scheme can be used to write purely functional programs, but that certainly isn't its only use. There is also support for OOP via add-ons.

 

[IHateMyJob2004]

nevermind