package main

import (
	"fmt"
	"runtime"
	"time"
)

func condition() {
	for i := 0; i < 10; i++ {
		if i%2 == 0 {
			fmt.Println("this number is even: ", i)
		}
	}
}

func sqrt(x float64) float64 {
	z := 1.0
	for i := 0; i < 10; i++ {
		z -= (z*z - x) / (z * 2)
		fmt.Println(z)
	}
	return z
}

func main() {
	defer condition()
	fmt.Println(sqrt(2))

	fmt.Print("Go runs on ")
	switch os := runtime.GOOS; os {
	case "Windows":
		fmt.Println("MacOs.")
	case "Linx":
		fmt.Println("Linux.")
	default:
		fmt.Printf("%s.\n", os)
	}

	fmt.Println("*******************")
	fmt.Println("When's Saturday?")
	today := time.Now().Weekday()
	switch time.Saturday {
	case today + 0:
		fmt.Println("Today.")
	case today + 1:
		fmt.Println("Tomorrow.")
	case today + 2:
		fmt.Println("In two days.")
	default:
		fmt.Println("Too far away.")
	}

}