都是一个货色，要么使用无缓冲channel, 要么使用有缓冲chan+waitgroup等待协程退出，或者使用全局变量判断是否终止协程

2个协程交替打印奇数和偶数

无缓冲channel实现

package mainimport "fmt"func main() {maxval := 10ch1 := make(chan struct{})ch2 := make(chan struct{})close := make(chan struct{})go func() {for i := 1; i <= maxval ; i++ {if i%2 == 1 {<-ch1fmt.Printf("%d\n", i)ch2 <- struct{}{}}}}()go func() {for i := 1; i <= maxval ; i++ {if i%2 == 0 {<-ch2fmt.Printf("%d\n", i)if i == maxval {close <- struct{}{}} else {ch1 <- struct{}{}}}}}()ch1 <- struct{}{}<-close
}

有缓冲channel实现

package mainimport "fmt"func main() {maxval := 10ch1 := make(chan struct{}, 1)ch2 := make(chan struct{}, 1)close := make(chan struct{})go func() {for i := 1; i <= maxval; i++ {if i%2 == 1 {<-ch1fmt.Printf("%d\n", i)ch2 <- struct{}{}}}}()go func() {for i := 1; i <= maxval; i++ {if i%2 == 0 {<-ch2fmt.Printf("%d\n", i)ch1 <- struct{}{}}}close <- struct{}{}}()ch1 <- struct{}{}<-close
}

有缓冲channel+ waitgroup

package mainimport ("fmt""sync"
)func main() {maxval := 10ch1 := make(chan struct{}, 1)ch2 := make(chan struct{}, 1)wg := &sync.WaitGroup{}wg.Add(2)go func() {defer wg.Done()for i := 1; i <= maxval; i++ {if i%2 == 1 {<-ch1fmt.Printf("%d\n", i)ch2 <- struct{}{}}}}()go func() {defer wg.Done()for i := 1; i <= maxval; i++ {if i%2 == 0 {<-ch2fmt.Printf("%d\n", i)ch1 <- struct{}{}}}}()ch1 <- struct{}{}wg.Wait()
}

N个协程交替打印1到maxVal

package mainimport ("fmt"
)func main() {cur := 0maxval := 10N := 3chs := make([]chan struct{}, 3)closeCh := make(chan struct{})for i := 0; i < N; i++ {chs[i] = make(chan struct{})}for i := 0; i < N; i++ {go func(i int) {for {_, ok := <-chs[i]if !ok {//fmt.Printf("go %d close\n", i)return}fmt.Printf("go %d print %d\n", i, cur)if cur == maxval {closeCh <- struct{}{}return}cur++chs[(i+1)%N] <- struct{}{}}}(i)}chs[0] <- struct{}{}<-closeChfor i := 0; i < N; i++ {close(chs[i])}fmt.Printf("main end\n")
}

使用三个协程分别打印A,B,C打印这个100次

package mainimport ("fmt"
)func main() {cnt := 2N := 3chs := make([]chan struct{}, 3)closeCh := make(chan struct{})for i := 0; i < N; i++ {chs[i] = make(chan struct{}, 1)}for i := 0; i < N; i++ {go func(i int) {b := byte('A') + byte(i)for j := 0; j < cnt; j++ {<-chs[i]fmt.Printf("go %d print %c\n", i, b)chs[(i+1)%N] <- struct{}{}}if i == N-1 {closeCh <- struct{}{}}}(i)}chs[0] <- struct{}{}<-closeChfor i := 0; i < N; i++ {close(chs[i])}fmt.Printf("main end\n")
}