Array sum using Loop, Goroutines and Recursion in Go

main.go

package main

import "fmt"

const (
	BATCH_COUNT = 5
)

func loopSum(s []int) int {
	sum := 0
	for _, v := range s {
		sum += v
	}
	return sum
}

func sum(s []int, c chan int) {
	sum := 0
	for _, v := range s {
		sum += v
	}
	c <- sum // send sum to c
}

func channelSum(s []int) int {
	c := make(chan int)
	numberOfSumBatch := len(s)/BATCH_COUNT

	for i := 0; i < numberOfSumBatch; i++ {
		go sum(s[i*BATCH_COUNT:(i+1)*BATCH_COUNT], c)
	}

	chanSum := 0
	for i := 0; i < numberOfSumBatch; i++ {
		chanSum += <-c	// receive from c
	}
	return chanSum
}

func recursiveSum(s []int) int {
	if len(s) == 0 {
		return 0
	}
	return s[0] + recursiveSum(s[1:])
}

func main() {
	s := []int{1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181, 6765, 10946, 17711, 28657, 46368, 75025, 121393}

	fmt.Println("Sum from channel: ", channelSum(s))

	fmt.Println("Sum from loop: ", loopSum(s))

	fmt.Println("Sum from recursive: ", recursiveSum(s))
}

// Output:
// Sum from channel:  317809
// Sum from loop:  317809
// Sum from recursive:  317809