Go language basic cache channel channel

buffered channel

For non-buffered channels, both sending and receiving are blocked
. With buffered channels, there is a buffer area that can continue to send and receive data.
The make(chan T, size)
buffer is full, the program will be blocked
ch1:=make(chan int, 5)
ch1 <- 100//no blocking, because there is a cache
ch1 <- 200//
ch1 <- 300
ch1 <- 400
ch1 <- 500
...//buffer is full

ch1 <- 600 // blocked program

package main

import (
   "fmt"
   "strconv"
   "time"
)

func main () {
    /*
    Non-cached channel: make(chan T)
    Cached channel: make(chan T, size)
       cached channel, understood as a queue:
    non-cached, sending or receiving, all are blocked.
   Cached channel, buffered area When the data is full, it will block. .
    */
 ch1 := make ( chan int )            //uncached channel
 fmt.Println(len(ch1) , cap(ch1)) //0 0
    //ch1 <- 100//blocked, need other goroutines to release Block, otherwise deadlock
 ch2 := make ( chan int , 5 )         // buffered channel, buffer size is 5
 fmt.Println(len(ch2) , cap(ch2)) //0 5
 ch2 <-

      
         100                      //
   fmt.Println(len(ch2), cap(ch2)) //1 5
   //ch2 <- 200
   //ch2 <- 300
   //ch2 <- 400
   //ch2 <- 500
   //ch2 <- 600
fmt.Println("--------------")
   
   ch3 := make(chan string, 4)
   go sendData3(ch3)
   for {
      time.Sleep(1*time.Second)
      v, ok := <-ch3
      if !ok {
         fmt.Println( "Finished," , ok)
          break
       }
      fmt.Println( "\t The data read is: " , v)
   }

   fmt.Println("main...over...")
}

func sendData3(ch3 chan string) {
   for i := 0; i < 10; i++ {
      ch3 <- "数据" + strconv.Itoa(i)
      fmt.Println( "Sub-goroutine, write out the first " , i , "data" )
   }
   close(ch3)
}