fib with go routines

fibWithRoutines.go

package main

import (
	"fmt"
	"sync"
)

var wg sync.WaitGroup

func readFib(c <-chan int) {
	// Option 1
	// for val := range c {
	// 	fmt.Println(val)
	// }

	// Option 2
	for {
		var val int
		var ok bool
		if val, ok = <-c; !ok {
			break
		}
		fmt.Println(val)
	}
}

func fib(c chan<- int, n int) {
	fibArr := []int{1, 1}
	c <- fibArr[0]
	c <- fibArr[1]
	wg.Add(-2)

	next := 0
	for i := 2; i < n; i++ {
		defer wg.Done()
		next = fibArr[i-1] + fibArr[i-2]
		fibArr = append(fibArr, next)
		c <- next
	}
	close(c)
}

func routineFib(n int) {
	wg.Add(n)
	ch := make(chan int, n)
	go fib(ch, n)
	readFib(ch)
	wg.Wait()
}

func main() {
	routineFib(10)
}

/* Response
1
1
2
3
5
8
13
21
34
55
*/