main.go

package main

import (
	"fmt"
	"time"
)

// this is a person
type person struct {
	name string
	age  int
}

func main() {
	rangeFunc()
	timers()
}

func rangeFunc() {
	nums := []int{2, 3, 4}
	sum := 0
	for _, num := range nums {
		sum += num
	}
	fmt.Println("sum:", sum)

	for i, num := range nums {
		if num == 3 {
			fmt.Println("index:", i)
		}
	}

	kvs := map[string]string{"a": "apple", "b": "banana"}
	for k, v := range kvs {
		fmt.Printf("%s -> %s\n", k, v)
	}

	for k := range kvs {
		fmt.Println("key:", k)
	}

	for i, c := range "go" {
		fmt.Println(i, c)
	}
}

func timers() {
	timer1 := time.NewTimer(2 * time.Second)

	<-timer1.C
	fmt.Println("Timer 1 fired")

	timer2 := time.NewTimer(time.Second)

	go func() {
		<-timer2.C
		fmt.Println("Timer 2 fired")
	}()
	stop2 := timer2.Stop()
	if stop2 {
		fmt.Println("Timer 2 stopped")
	}
	time.Sleep(2 * time.Second)
}

func structs() {
	fmt.Println(person{"Bob", 20})
	fmt.Println(person{name: "Alice", age: 30})
	fmt.Println(person{name: "Fred"})
	fmt.Println(&person{name: "Ann", age: 40})
	fmt.Println(newPerson("Jon"))

	s := person{name: "Sean", age: 50}
	fmt.Println(s.name)

	sp := &s
	fmt.Println(sp.age)

	sp.age = 51
	fmt.Println(sp.age)
}

func newPerson(name string) *person {
	p := person{name: name}
	p.age = 42
	return &p
}