go - Golang Parallel -

i new golang , trying understand concurrency , parallel. read below mentioned article concurrency , parallel. have executed same program. not getting same ( mixed letter & character ) output. getting first letters characters. seems concurrency working not parallel not.

article says add runtime.gomaxprocs(4) make parallel.

why not getting parallel out ?

i using 4 core cpu system , go version 1.8.2

https://www.goinggo.net/2014/01/concurrency-goroutines-and-gomaxprocs.html

i know if add sleep can see parallel output, per concurrency concept . parallelism says if system has more 1 cpu, each thread run in 1 cpu , becomes parallel process. question here why not getting parallel output though system has 4 core , added runtime.gomaxprocs(4), .

go program

package main  import (     "fmt"     "runtime"     "sync" )  func main() {     runtime.gomaxprocs(2)      var wg sync.waitgroup     wg.add(2)      fmt.println("starting go routines")     go func() {         defer wg.done()          char := ‘a’; char < ‘a’+26; char++ {             fmt.printf("%c ", char)         }     }()      go func() {         defer wg.done()          number := 1; number < 27; number++ {             fmt.printf("%d ", number)         }     }()      fmt.println("waiting finish")     wg.wait()      fmt.println("\nterminating program") } 

my output

starting go routines waiting finish 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 b c d e f g h j k l m n o p q r s t u v w x y z terminating program 

expected output ( not same , parallel output )

starting go routines waiting finish b 1 2 3 4 c d e f 5 g h 6 7 j 8 k 9 10 11 12 l m n o p q 13 r s 14 t 15 u v 16 w 17 x y 18 z 19 20 21 22 23 24 25 26 terminating program 

in opinion there 2 troubles can in code. first idea:

 runtime.gomaxprocs(2) 

using row allow 2 workers, starting 3 go routines (main takes one).

but main problem go routines finished fast. adding

time.sleep(100000) 

will solve problem. package main

import (     "fmt"     "runtime"     "sync" )  func main() {     runtime.gomaxprocs(3)      var wg sync.waitgroup     wg.add(2)      fmt.println("starting go routines")     go func() {         defer wg.done()         char := 'a'; char < 'a'+26; char++ {             := 0; < 10000; i++ {                 _ = * 2             }             fmt.printf("%c ", char)         }     }()      go func() {         defer wg.done()         number := 1; number < 27; number++ {             := 0; < 10000; i++ {                 _ = * 2             }             fmt.printf("%d ", number)         }     }()      fmt.println("waiting finish")     wg.wait()      fmt.println("\nterminating program") } 

in case i've tried not use sleep function, because change thread status in scheduler. , have result.

starting go routines waiting finish 1 2 3 4 5 b 6 c d 7 8 e f 9 g h 10 j 11 k 12 l m 13 n 14 o p q 15 r 16    s 17 t u 18 v 19 w 20 x y 21 z 22 23 24 25 26  terminating program