simple_pool.go

package main

import "sync"

func main() {
	jobChan := make(chan int)
	resChan := make(chan int)
	squareGroup := new(sync.WaitGroup)
	
	// The workers
	for i := 0; i < 5; i++ {
		squareGroup.Add(1)
		go func() {
			for n := range jobChan {
				resChan <- n * n
			}
			squareGroup.Done()
		}()
	}
	
	// The "submitter"
	go func() {
		for i := 0; i < 10; i++ {
			jobChan <- i
		}
		close(jobChan)
		squareGroup.Wait()
		close(resChan)
	}()
	
	// Collect the results back in the main goroutine
	for s := range resChan {
		println(s)
	}
}