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mirror of https://github.com/golang/go synced 2024-11-23 00:50:05 -07:00
go/doc/progs/sieve.go
Rob Pike 81672ef15b fix some typos, mostly
R=gri
OCL=16161
CL=16161
2008-09-29 20:06:48 -07:00

37 lines
895 B
Go

// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package main
// 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 % prime != 0 {
out <- i // Send 'i' to channel 'out'.
}
}
}
// The prime sieve: Daisy-chain Filter processes together.
func main() {
ch := new(chan int); // Create a new channel.
go Generate(ch); // Start Generate() as a goroutine.
for {
prime := <-ch;
print(prime, "\n");
ch1 := new(chan int);
go Filter(ch, ch1, prime);
ch = ch1
}
}