RE: Where is the syntax error

Thanks, 
 
I will do that later. Things like tail recursion is not discussed in the first three chapters. 
 
Roelof

 
To: [email protected]
From: [email protected]
Date: Fri, 27 Feb 2015 12:19:26 +0000
Subject: Re: "ocaml_beginners"::[] Where is the syntax error














 

 



  


    
      
      
      Hi,



>Now Im stuck at this problem : > 

>let rec power a b = if b = 1 then a * 1 else a * power ( b - 1) ;;

>

>Error: This expression has type int -> int

>       but an expression was expected of type int

The error message is telling you that the invocation of power is

missing an argument.  Also, I suggest using meaningful names for



your arguments, and note that multiplying by 1 is just silly.

Here's a better version:

  let rec power base exp = if exp = 1 then base else base * power base (exp - 1)



Note that the function above is neither tail-recursive nor resilient

against bad arguments (try giving it a negative exponent!).  Consider

improving it further as an exercise...



Best regards,

Dario Teixeira