Furthermore, The syntax you're using is not correct.
If you want to define functions inside your function ex1_17, use letfn.
Something along the line:
(defn ex1_17 []
(letfn [(double [x] (+ x x))
(halve [x] (/ x 2))
(mult [a b]
(cond
(= b 0) 0
(even? b) (* (double a) (halve b))
:else (+ a (* a (- b 1)))))]
(println (mult 5 5))))
I prefer not to mess with the default function so i redefined your * by mult
Antoine
2012/5/17 eniotna <eniotn...@gmail.com>
> Hi,
>
> Look at your parenthesis.
> You did not close your first function.
>
> Antoine
>
>
> 2012/5/17 Sargash <gerby...@gmail.com>
>
>> Hi!
>>
>> I have a problem. With that code:
>>
>> ; =======================================
>> ; ex 1.17 multiply
>> (defn ex1_17 []
>> (defn double [x] (+ x x))
>> (defn halve [x] (/ x 2))
>>
>> (defn * [a b]
>> (cond
>> (= b 0) 0
>> (even? b) (* (double a) (halve b))
>> :else (+ a (* a (- b 1)))))
>>
>> (println (* 5 5))
>> )
>> (ex1_17 )
>>
>> I gave that exception:
>>
>> Exception in thread "main" java.lang.NullPointerException, compiling:
>> (D:\workprivate\ll\1\src\first.clj:3)
>> at clojure.lang.Compiler.analyzeSeq(Compiler.java:6462)
>> at clojure.lang.Compiler.analyze(Compiler.java:6262)
>> at clojure.lang.Compiler.analyzeSeq(Compiler.java:6443)
>> at clojure.lang.Compiler.analyze(Compiler.java:6262)
>> at clojure.lang.Compiler.access$100(Compiler.java:37)
>> at clojure.lang.Compiler$DefExpr$Parser.parse(Compiler.java:518)
>> at clojure.lang.Compiler.analyzeSeq(Compiler.java:6455)
>> at clojure.lang.Compiler.analyze(Compiler.java:6262)
>> at clojure.lang.Compiler.analyze(Compiler.java:6223)
>> at clojure.lang.Compiler.eval(Compiler.java:6515)
>> at clojure.lang.Compiler.load(Compiler.java:6952)
>> at clojure.lang.Compiler.loadFile(Compiler.java:6912)
>> at clojure.main$load_script.invoke(main.clj:283)
>> at clojure.main$script_opt.invoke(main.clj:343)
>> at clojure.main$main.doInvoke(main.clj:427)
>> at clojure.lang.RestFn.invoke(RestFn.java:408)
>> at clojure.lang.Var.invoke(Var.java:415)
>> at clojure.lang.AFn.applyToHelper(AFn.java:161)
>> at clojure.lang.Var.applyTo(Var.java:532)
>> at clojure.main.main(main.java:37)
>> at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
>> at
>> sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:
>> 39)
>> at
>>
>> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:
>> 25)
>> at java.lang.reflect.Method.invoke(Method.java:597)
>> at com.intellij.rt.execution.application.AppMain.main(AppMain.java:
>> 120)
>> Caused by: java.lang.NullPointerException
>> at clojure.lang.Compiler$ObjExpr.emitVar(Compiler.java:4774)
>> at clojure.lang.Compiler$DefExpr.emit(Compiler.java:418)
>> at clojure.lang.Compiler$BodyExpr.emit(Compiler.java:5659)
>> at clojure.lang.Compiler$FnMethod.doEmit(Compiler.java:5215)
>> at clojure.lang.Compiler$FnMethod.emit(Compiler.java:5069)
>> at clojure.lang.Compiler$FnExpr.emitMethods(Compiler.java:3600)
>> at clojure.lang.Compiler$ObjExpr.compile(Compiler.java:4233)
>> at clojure.lang.Compiler$FnExpr.parse(Compiler.java:3732)
>> at clojure.lang.Compiler.analyzeSeq(Compiler.java:6453)
>> ... 24 more
>>
>> Could you tell me where I wrong?
>>
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>
>
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