An answer of the exercise: Loops and Functions on a tour of Go

answer_exercise_gotour.go

package main

import (
	"fmt"
	"math"
)

const Delta = 0.0001

func isConverged(d float64) bool {
	if d < 0.0 {
		d = -d
	}
	if d < Delta {
		return true
	}
	return false
}

func Sqrt(x float64) float64 {
	z := 1.0
	tmp := 0.0
	for {
		tmp = z - (z * z - x) / 2 * z
		if d := tmp - z; isConverged(d) {
			return tmp
		}
		z = tmp
	}
	return z
}

func main() {
	attempt := Sqrt(2)
	expected := math.Sqrt(2)
	fmt.Printf("attempt = %g (expected = %g) error = %g\n",
		attempt, expected, attempt - expected)
}

package main

import (
"fmt"
"math"
)

func Sqrt(x float64) float64 {
z:=1.0

for n:= 1;n < 10;n++ {
	z = z - ((z*z - x) / (2*z))
}
return z

}

func main() {
y := 169.
fmt.Println(Sqrt(y))
fmt.Println(math.Sqrt(y))
}

func Sqrt(x float64) float64 {
var z, tmp float64 = 1.0, 0.
for ; math.Abs(z - tmp) >= 1e-8 ; z, tmp = z - (zz-x)/(2z), z {}
return z
}

package main

import (
"fmt"
)

func Sqrt(x float64) float64 {
z := float64(1)
for i := 1; i <= 10; i++ {
nextZ := z - (zz-x)/(2z)
if nextZ == z {
return z
} else {
z = nextZ
fmt.Println(z, i)
}
}
return z
}

func main() {
p := 2.0
fmt.Println(Sqrt(p))
}

package main

import (
"fmt"
"math"
)

func Sqrt(x float64) float64 {
z := 1.0
iterations := 0

for i := 0; i <= 100; i++ {

	z -= (z*z - x) / (2 * z)
	iterations += 1

	if z == math.Sqrt(x) {
		break
	}
}
fmt.Println(z, "iterations: ", iterations)
return z

}

func main() {
var x float64 = 102444
fmt.Println("Guess: ", Sqrt(x))
fmt.Println("Math module: ", math.Sqrt(x))
}

package main

import (
	"fmt"
	"math"
)

func Sqrt(x float64) float64 {
	prev, z := 0.0, 1.0
	
	for math.Abs(prev - z) > 1e-3 {
		prev = z
		z -= (z*z - x) / (2*z)
	}
	
	return z
}

func main() {
	n := 2.0
	g := Sqrt(n)
	a := math.Sqrt(n)
	d := math.Abs(g - a)
	fmt.Printf("Guessed: %f  Actual: %f  Delta: %f\n", g, a, d)
}