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object Sqrt {
def abs(x:Double) = if (x < 0) -x else x
def sqrt(x: Double) = {
def sqrtIter(guess: Double): Double =
if (isGoodEnough(guess)) guess
else sqrtIter(improve(guess))
def isGoodEnough(guess: Double) =
abs(guess * guess - x ) /x < 0.001
def improve(guess: Double) =
(guess + x / guess) / 2
sqrtIter(1.0)
}
def run =
println(sqrt(2))
println(sqrt(0.001))
println(sqrt(0.1e-20))
println(sqrt(1.0e20))
println(sqrt(1.0e50))
}
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