go routine concurrency example to print sequential numbers using 2 goroutines - one for odd and one for even.

concurrency-example.go

package main

import (
  "fmt"
  "time"
)

func printNum(waitCh, pauseCh chan int, start, end int) {
  fmt.Println("Inside print")
  <-waitCh
  for i := start; i <= end; i += 2 {
    fmt.Println(i)

    pauseCh <- i
    <-waitCh
  }
  close(pauseCh)
}

func main() {
  pauseCh := make(chan int)
  waitCh := make(chan int)

  go printNum(waitCh, pauseCh, 0, 6)
  go printNum(pauseCh, waitCh, 1, 6)
  waitCh <- 1

  time.Sleep(2 * time.Second)
}