rounding numbers in rebol

[jchunn]

Hello,
Can someone show me how to round a number to 2 decimal places?
Spent all morning trying the round function, but can't seem to
get it.
Thanks,

[CarlRead]

Use ROUND/TO and add a decimal value.  ie...

>> round/to 123.4567 .05
== 123.45
>> round/to 123.4567 .005
== 123.455

(Someone else can explain how the different decimal values affect the result;)

Or if it's just formatting you want, then your number will have to be turned into a string.  With this being one way to do it...

>> n: 123.4567
>> head clear next next find/tail join mold to-decimal n "00" #"."
== "123.45"
>> n: 1
== 1
>> head clear next next find/tail join mold to-decimal n "00" #"."
== "1.00"

Which could be improved by turning it into a function...

Code:

format: func [
    num [integer! decimal!]
    places [integer!]
][
    head clear skip find/tail join mold to-decimal num "00" #"." places
]

Which allows...

>> format 123.4567 2
== "123.45"
>> format 123.4567 3
== "123.456"
>> format 123.4 3
== "123.400"
>> format 1 2
== "1.00"

Hope that helps.

[jchunn]

Thank you very much, Carl!
Sincerely,
Jan Chunn