mirror of
https://github.com/golang/go
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43 lines
1.0 KiB
Go
43 lines
1.0 KiB
Go
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// $G $F.go && $L $F.$A # don't run it - goes forever
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// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package Main
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// Send the sequence 2, 3, 4, ... to channel 'ch'.
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func Generate(ch *chan> int) {
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for i := 2; ; i++ {
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>ch = i // Send 'i' to channel 'ch'.
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}
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}
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// Copy the values from channel 'in' to channel 'out',
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// removing those divisible by 'prime'.
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func Filter(in *chan< int, out *chan> int, prime int) {
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for {
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i := <in; // Receive value of new variable 'i' from 'in'.
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if i % prime != 0 {
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>out = i // Send 'i' to channel 'out'.
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}
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}
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}
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// The prime sieve: Daisy-chain Filter processes together.
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func Sieve() {
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ch := new(chan int); // Create a new channel.
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go Generate(ch); // Start Generate() as a subprocess.
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for {
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prime := <ch;
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printf("%d\n", prime);
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ch1 := new(chan int);
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go Filter(ch, ch1, prime);
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ch = ch1
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}
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}
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func Main() {
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Sieve()
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}
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