go并发实现素数筛的代码

package main
 
import (
	"fmt"
)
 
// Send the sequence 2, 3, 4, ... to channel 'ch'.
func generate(ch chan int) {
	for i := 2; ; i++ {
		ch <- i // Send 'i' to channel 'ch'.
	}
}
 
// Copy the values from channel 'in' to channel 'out',
// removing those divisible by 'prime'.
func filter(in, out chan int, prime int) {
	for {
		i := <-in // Receive value of new variable 'i' from 'in'.
		if i == 4{
			fmt.Println(prime)
		}
		if i%prime != 0 {
			out <- i // Send 'i' to channel 'out'.
		}
	}
}
 
// The prime sieve: Daisy-chain filter processes together.
func main() {
	ch := make(chan int) // Create a new channel.
	go generate(ch)   // Start generate() as a goroutine.
	for i:=0;i<10;i++ {
		prime := <-ch
		fmt.Println(&ch)
		fmt.Print(prime, " ")
		ch1 := make(chan int)
		go filter(ch, ch1, prime)
		ch = ch1
	}
}