golang 并发问题

Question

import("fmt""runtime")/*结果：有时99有时100*/varcounter_numintconstMAXSIZE=100funcCount_num(chchanint){counter_num++ch

Answer 1

packagemain
import(
"fmt"
"runtime"
"sync/atomic"
)
/*
结果：
有时99
有时100
*/
varcounter_numuint32=0
constMAXSIZE=100
funcCount_num(chchanuint32){
atomic.AddUint32(&counter_num,1)
ch<-counter_num
}
funcmain(){
runtime.GOMAXPROCS(runtime.NumCPU())
varchs[MAXSIZE]chanuint32
fori:=0;ichs[i]=make(chanuint32)
goCount_num(chs[i])
}
fori,ch:=rangechs{
print("-----",i,"\n")
print(<-ch,"\n")
}
fmt.Println(counter_num)
}