Go Language programming Music library code

There are some code errors and omissions in the Go Language programming book, and here is a small piece of code that is modified and added.

---start, I also search a Baidu, mostly are the same, and in the Remove code block still have some problems (cannot be passed name).

All right!! Not much to say. All the code is shown below.

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Paste the entry file first.

Mplayer.go

package mainimport  (     "Bufio"      "FMT"       "OS"      "StrConv"      "strings"      "mplayer/ Library " //Here is the directory structure Oh, don't do it, SRC under the MPlayer directory of the Library directory     " MPLAYER/MP " // The MP directory under the MPlayer directory under SRC) func handlelibcommands (tokens []string)  {    if  Len (tokens)  < 2 {        fmt. Println ('        enter following commands to control  the player:       lib list -- View the  Existing music lib       lib add <name><artist ><source><type> -- Add a music to the music lib        lib remove&nbSP; serial number  -- Remove the specified music from the lib         ')         return    }     switch tokens[1] {    case  "List":         fmt. PRINTLN ("Serial number   MP3_id     name          author            Paths                               Type ")         for i := 0; i < lib . Len ();  i++ {            e, _ : = lib. Get (i)             fmt. Printf ("%-4d  %-8s  %-10s  %-12s  %-20s            %-5s\n ",  i+1, e.id, e.name, e.artist, e.source, e. Type)             //fmt. Println (" , i+1, ": ", "   ", e.id, "     ", e.name, "       ", e.artist, "     ", e.source, "      ",  e.type)         }    case " Add ":         {             if len (Tokens)  == 6 {                 id++                 lib. ADD (&Library. Musicentry{strconv. Itoa (ID),                 &NBSP;&NBSP;&NBSP;&NBSP;TOKENS[2],&NBSP;TOKENS[3],&NBSP;TOKENS[4],&NBSP;TOKENS[5]})              } else {                 fmt. Println ("usage: lib add <name><artist><source><type>")              }        }     case  "Remove":         if len (Tokens)  == 3 {            index, _  := strconv. Atoi (tokens[2])             //fmt. PRINTLN (Index)      &nbsP;      lib. Remove (index)             fmt. PRINTLN ("Serial number   MP3_id     name          author            Paths                               Type ")             for i := 0;  i < lib. Len (); i++ {                 e, _ := lib. Get (i)                 fmt. Printf ("%-4d  %-8s  %-10s  %-12s  %-20s            %-5s\n ",  i+1, e.id, e.name, e.artist, e.source, e.type)              }        } else {             fmt. Println ("usage: lib remove <id>")         }     default:        fmt. Println ("Unrecognized lib command:",  tokens[1])     }}func  Handleplaycommand (tokens []string)  {    if len (tokens)  != 2  {        fmt. Println ("usage: play <name>")         return     }    e := lib. Find (tokens[1])     if e == nil {    &nbsP;   fmt. Println ("The music", tokens[1],  "does not exist.")         return    }    mp. Play (E.source, e.type)}var lib *library. Musicmanagervar id int = 0func main ()  {    lib =  Library. Newmusicmanager ()     fmt. Println ('        enter following commands to control  the player:       lib list -- View the  Existing music lib       lib add <name><artist ><source><type> -- Add a music to the music lib        lib remove < Serial Number > -- Remove the  Specified music from the lib       play <name> -- play the  specified music       q | e  -- quit |  exit   ')     r := bufio. Newreader (OS. Stdin)     for {        fmt. Print ("enter command-> ")         rawline, _, _  := r.readline ()         line := string (RawLine)         if line ==  "Q"  | |  line ==  "E"  {             Break        }        tokens  := strings. Split (line,  " ") &NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;&NBSP;IF&Nbsp;tokens[0] ==  "Lib"  {             handlelibcommands (Tokens)         } else if tokens [0] ==  "Play"  {             Handleplaycommand (Tokens)         } else {             fmt. Println ("Unrecognized command:",  tokens[0])         }     }}

Manager.go//In the Library directory under the MPlayer directory

package libraryimport  (     "errors"      "FMT") type  Musicentry struct {    id string    name string     Artist string    Source string     Type string}type musicmanager struct {    musics []musicentry} Func newmusicmanager ()  *musicmanager {    return &musicmanager{ Make ([]musicentry, 0)}}func  (M *musicmanager)  len ()  int {     return len (m.musics)}func  (M *musicmanager)  get (index int)   (music * Musicentry, err error)  {    if index < 0 | |  index >= len (m.musics)  {        return  Nil, errors. New ("Index out of range. ")     }    //fmt. Println (M)     return &m.musics[index], nil}func  (M *musicmanager)  find (name string)  *musicentry {    if len (m.musics)  ==  0 {        return nil    }     for _, m := range m.musics {         if m.Name == name {             return &m        }     }    return nil}func  (M *musicmanager)  add (music * Musicentry)  {    m.musics = append (m.musics, *music)}func  (M  *musicmanager)  remove (index int)  *musicentry {     if index < 0 | |  index > len (m.musics)  {        fmt. PRINTLN ("Please re-select the deleted sequence number ...")         return nil    }     removedMusic := &m.musics[index-1]    //  Delete an element from an array slice      if index < len (m.musics)  { //  intermediate elements          m.musics = append (M.musics[:index-1], m.musics[index:] ...)     } else { //  Delete the last element          //fmt. Println ("Delete Last")         m.musics = m.musics[:index-1]     }    return removedmusic}

Mp3.go The MP directory under the//mplayer directory

package mpimport  (     "FMT"      "Time") Type mp3player  struct {    stat int    progress int}type  Wavplayer struct {    stat int    progress int} func  (P *mp3player)  play (source string)  {    fmt. Println ("Playing mp3 music",  source)     p.progress = 0     for p.progress < 100 {         time. Sleep (100 * time.millisecond)  //   pretend to be playing         fmt. Print (".")         p.progress += 10    }     fmt. Println ("\nfinished playing",  source)}func  (p *wavplayer)  play (source string) &NBsp {    fmt. Println ("Playing wav music",  source)     p.progress = 0     for p.progress < 100 {         time. Sleep (100 * time.millisecond)  //   pretend to be playing         fmt. Print (".")         p.progress += 10    }     fmt. Println ("\nfinished playing",  source)}

Play.go under the MP directory in the//mplayer directory

Package Mpimport "FMT" type Player interface {play (source string)}func play (source, mtype string) {var P player Switch Mtype {case ' MP3 ': p = &mp3player{} case "WAV": P = &wavplayer{} DEFAULT:FM T.println ("Unsupported music type", Mtype) return} p.play (source)}

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Please leave a message if there is any omission or code error. You are welcome to correct the corrections.

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Go Language programming Music library code