| // 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. |

| // Test concurrency primitives: classical inefficient concurrent prime sieve. |

| // Generate primes up to 100 using channels, checking the results. |

| // This sieve consists of a linear chain of divisibility filters, |

| // equivalent to trial-dividing each n by all primes p ≤ n. |

| // Send the sequence 2, 3, 4, ... to channel 'ch'. |

| func Generate(ch chan<- int) { |

| ch <- i // Send 'i' to channel 'ch'. |

| // Copy the values from channel 'in' to channel 'out', |

| // removing those divisible by 'prime'. |

| func Filter(in <-chan int, out chan<- int, prime int) { |

| for i := range in { // Loop over values received from 'in'. |

| out <- i // Send 'i' to channel 'out'. |

| // The prime sieve: Daisy-chain Filter processes together. |

| func Sieve(primes chan<- int) { |

| ch := make(chan int) // Create a new channel. |

| go Generate(ch) // Start Generate() as a subprocess. |

| // Note that ch is different on each iteration. |

| go Filter(ch, ch1, prime) |

| a := []int{2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97} |

| for i := 0; i < len(a); i++ { |

| if x := <-primes; x != a[i] { |