Go (golang) Advanced Tutorials - Mutex and Waitgroup, Console Input

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#golang #go #concurrency #waitgroups #mutex

Console input
--------------------------
-----------------------
package main
import (
"bufio"
"os"
"fmt"
)
func main(){
reader := bufio.NewReader(os.Stdin)
scanner := bufio.NewScanner(os.Stdin)
text,_ := reader.ReadString('\n') //Read a line
fmt.Println(text)

c,size,_:=reader.ReadRune() //Read single char
fmt.Println(c)
fmt.Println(size)

scanner.Scan() //Console input
fmt.Println(scanner.Text())

}

Waitgroup
-------------------
---------------------
package main
import (
"fmt"
"sync"
)
var count=0
func countHandler(myWaitGroup *sync.WaitGroup){
count++;
myWaitGroup.Done(); //Notify waitgroup of completion
}
func main(){
var myWaitGroup sync.WaitGroup

for i:=1;i<500;i++ {
myWaitGroup.Add(1) //Wait group counter incremented
go countHandler(&myWaitGroup)
}

myWaitGroup.Wait()
fmt.Println("Value :",count)
}

------------------------
package main
import (
"fmt"
"sync"
)
var count=0
func countHandler(myWaitGroup *sync.WaitGroup,mutex *sync.Mutex){
mutex.Lock() //Mutual Exclusive Lock
count++;
mutex.Unlock() //Releases lock
myWaitGroup.Done(); //Notify waitgroup of completion
}
func main(){
var myWaitGroup sync.WaitGroup
var mutex sync.Mutex

for i:=1;i<=500;i++ {
myWaitGroup.Add(1) //Wait group counter incremented
go countHandler(&myWaitGroup,&mutex)
}

myWaitGroup.Wait()
fmt.Println("Value :",count)
}