haskell - Conversion between Int and fractional values -

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i programming in haskell , having trouble following code:

exactrootlist :: int -> int -> [int] exactrootlist ini end =        [x | x<-[ini .. end],  (floor (sqrt x)) == (ceiling (sqrt x))]

then, when execute:

> hugs myprogram.hs

i get

error instances of (floating int, realfrac int) required definition of exactrootlist

i not understand error.

my program should show list of numbers have exact root 4 or 9, on interval [a, b] , b 2 params of function. example:

exactrootlist 1 10

it must return

1 4 9

because between 1 , 10 1, 4 , 9 have exact root.

greetings!

if @ type of sqrt see works on types instance of floating:

> :t sqrt sqrt :: floating => ->

as know, int not floating point value. need convert ints (the variable x) using fromintegral:

[x | x<-[ini .. end],  let = fromintegral x                        in (floor (sqrt a)) == (ceiling (sqrt a))]

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