This code below, 1 -- 30 of prime Numbers, why in the run results 9 will be printed, should is not a prime, 9 additional runtime a number printed several times, how to modify the code to get him a number only print again,

CodePudding user response:

Judgement is prime is not playing so well

Logic has a problem, no ready-made code, see red part

 
Func putNum (numChan chan int, n int) {
For I:=2; i <=n; I++ {
NumChan & lt; -i 
FMT. Println (I, "has been in the pipeline") 
} 
Close (numChan) 
FMT. Println (" numChan closed ") 
} 
Func solve (numChan chan int, resultChan chan int, exitChan chan bool) {
//time. Sleep (time. Microsecond) 
For {
Num, ok:=& lt; - numChan 
//can't take the data out, said the current coroutines task to complete, could leave 
if ! Ok {
Break 
} 
 
Flag:=true 
For I:=2; i If I num %==0 {
Flag=false 
Break 
} 
} 
The if flag {
ResultChan & lt; - num 
FMT. Println (" get "of prime num) 
} 
}  
//tell the other coroutines, coroutines mission completed 
ExitChan & lt; - true 
FMT. Println (" a collaborators process took less than data and exit ") 
} 
Func main () {
NumChan:=make (chan int, 1000) 
ResultChan:=make (chan int, 1000) 
ExitChan:=make (chan bool, 8) 
Go putNum numChan, (8000) 
//open 8 collaborators cheng 
For I:=0; i <8; I++ {
Go solve (numChan resultChan, exitChan) 
} 
//blocking the main thread, wait for after all coroutines work 
Go func () {
For I:=0; i <8; I++ {
//if there is no desirable will wait 
<- exitChan 
} 
//when after eight are close collaborators cheng can close resultChan 
Close (resultChan) 
FMT. Println (" resultChan closed ") 
} () 
//remove the result here can be used for - range, although resultChan is closed by coroutines, 
//here, but the main thread running all coroutines have to complete the task, when the resultChan must be shut down 
For value:=range resultChan {
FMT. Println (value, "is a prime number") 
} 
FMT. Println (" the main thread to exit the ") 
} 

CodePudding user response:

17-29 lines, ~ ~ zha don't change color

CodePudding user response:

references and 蘤 old crepe reply: 3/f

17 to 29 lines, ~ ~ zha don't change color

So complicated, I just learned concurrent and channel, try thinking about writing your own first, seems to have learned back again wrote

CodePudding user response:

No, you want is just a fraction, the other is not, I had written many coroutines primes, you don't need to add concurrency and channels

CodePudding user response:

reference 5 floor and 蘤 old crepe reply:

no, you want is just a fraction, the other is not, I had written many coroutines prime Numbers, and you don't need to add concurrency and channel

Oh oh, I see, thank you

CodePudding user response:

Simple code it is ok to modify the

 
Func main () {
For I:=2; i <30; I++ {
J:=2 
For; J & lt; i; J++ {
If I % j==0 {
Break 
} 
} 
If I==j {
FMT. Println (I) 
} 
} 
} 

Output:

 
2 
3 
5 
7 
11. 
13 
17 
19 
23 
29