42 lines
862 B
Go
42 lines
862 B
Go
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package main
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import (
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"fmt"
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)
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func sum(a []int, c chan int) {
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s := 0
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for _, v := range a {
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s += v
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}
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c <- s
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}
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func main() {
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a := []int{7, 2, 8, -9, 4, 0}
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c := make(chan int)
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go sum(a[:len(a)/2], c)
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go sum(a[len(a)/2:], c)
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go sum(a, c)
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x, y, z := <-c, <-c, <-c
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fmt.Printf("%d %d %d\n", x, y, z)
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// panics with deadlock if buffer doesn't match reads from chan
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// throw: all goroutines are asleep - deadlock!
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c2 := make(chan int, 2)
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c2 <- 1
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c2 <- 2
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// must not do this without increasing buffer size: c2 <- 2
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fmt.Println(<-c2)
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fmt.Println(<-c2)
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// note that this chanel is buffered, and that we don't need to launch go
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// routines
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c_buffered := make(chan int, 10)
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sum(a[:len(a)/2], c_buffered)
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sum(a[len(a)/2:], c_buffered)
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sum(a, c_buffered)
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x, y, z = <-c_buffered, <-c_buffered, <-c_buffered
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fmt.Printf("%d %d %d\n", x, y, z)
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}
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