go basis (c)

A, mutex lock channel

package main

利用mutex：
//import (
//"fmt"
//"sync"
//)
//var x  = 0
//func increment(wg *sync.WaitGroup, m *sync.Mutex) {
//
//    m.Lock()
//    x = x + 1
//    m.Unlock()
//    wg.Done()
//}
//func main() {
//    var w sync.WaitGroup
//    var m sync.Mutex
//    for i := 0; i < 1000; i++ {
//        w.Add(1)
//        go increment(&w,&m)
//    }
//    w.Wait()
//    fmt.Println("final value of x", x)
//}


利用信道：
import (
    "fmt"
    "sync"
)
var x  = 0
func increment(wg *sync.WaitGroup, ch chan bool) {
    ch <- true
    x = x + 1
    <- ch
    wg.Done()
}
func main() {
    var w sync.WaitGroup
    ch := make(chan bool, 1)
    for i := 0; i < 1000; i++ {
        w.Add(1)
        go increment(&w, ch)
    }
    w.Wait()
    fmt.Println("final value of x", x)
}

Second, exception handling

// Exception Handling 
Package Penalty for main 

Import  " fmt " 

FUNC main () {
     // the defer delay the execution, after the implementation of the first registration, even if the function is a serious mistake, it will execute
     // the defer fmt.Println ( " xxxxxxx " )
     // fmt.Println the defer ( " yyyy " ) 
    f1 () 
    F2 () 
    F3 () 

} 
FUNC f1 () { 
    fmt.Println ( " f1 " ) 
} 
FUNC F2 () {
     // the defer fmt.Println ( " I need except oh a " )

     // the defer FUNC () {
     // recover () // recovery program
     //} () 
    The defer FUNC () { 
        IF OK:! = Recover (); OK = nil {
             // If the abnormality is not showing nil, if the abnormal value is expressed, the value is abnormal signal
             // exception handling 
            fmt .Println (OK) 
        } 
    } () 
    fmt.Println ( " F2 " )
     // the make var A = ([] int, 3,3 )
     //fmt.Println(a[4]) // exception handling off, allow the program to continue
     panic ( "wrong") // initiative thrown
     //fmt.Println ( " XXXXX " ) 
} 
FUNC F3 () { 
    fmt.Println ( " F3 " ) 
}