Study essay of Go 2019-10-24

向右看齐 2023-05-31 10:10 1阅读 0赞

# Study essay of Go 2019-10-24 #

## 1. Features ##

*  simple, fast and safe.
 *  parallel,intresting and open .
 *  memory management,array security,fast compilation.

## 2. Use ##

*  web server .
 *  higher development efficiency.
 *  game server.

## 3. Installation ##

download the installation package at [here][].

*  windows  
      Just run the msi file.
 *  Linux or Mac  
      extract the tar.gz file.  
      then export the ectract path to your environment PATH.

## 4. Hello world ##

First,create a file named helloworld.go.

package main
    
    import "fmt"
    
    func main(){
        fmt.Println("helllo world!")
    }

run with the follow command:

go run helloworld.go

you also can build it to a binary file,for example:

go build helloworld.go

and then run the binary file:

$./hellworld

#### Notice: ####

1.  Character ‘\{’ can not be placed on a single line,for example:

package main
    
    import "fmt"
    
    func main()
    {   //will throw an error
        fmt.Println("helllo world!")
    }

1.  In the go program a line represents the end of a statement,it means that you don’t need to end the statement with ‘;’.
2.  You can write single comment with ‘//’ or multi-line with ‘/\* \*/’,for example:

// I am single comment
    /*
    I am multi-line comment
    */

1.  Identifier rule:(A-Z,a-z,0-9,\_),but the first character must be a letter or and underscore and not a number or go language keywords.

## 5. Go language keywords ##

<table> 
 <tbody> 
  <tr> 
   <td>break</td> 
   <td>default</td> 
   <td>func</td> 
   <td>interface</td> 
   <td>select</td> 
  </tr> 
  <tr> 
   <td>case</td> 
   <td>defer</td> 
   <td>go</td> 
   <td>map</td> 
   <td>struct</td> 
  </tr> 
  <tr> 
   <td>chan</td> 
   <td>else</td> 
   <td>goto</td> 
   <td>package</td> 
   <td>switch</td> 
  </tr> 
  <tr> 
   <td>const</td> 
   <td>fallthrough</td> 
   <td>if</td> 
   <td>range</td> 
   <td>type</td> 
  </tr> 
  <tr> 
   <td>continue</td> 
   <td>for</td> 
   <td>import</td> 
   <td>return</td> 
   <td>var</td> 
  </tr> 
 </tbody> 
</table>

## 6. Predefined indentifier ##

<table> 
 <tbody> 
  <tr> 
   <td>append</td> 
   <td>bool</td> 
   <td>byte</td> 
   <td>cap</td> 
   <td>close</td> 
   <td>complex</td> 
   <td>complex64</td> 
   <td>complex128</td> 
   <td>uint16</td> 
  </tr> 
  <tr> 
   <td>copy</td> 
   <td>false</td> 
   <td>float32</td> 
   <td>float64</td> 
   <td>imag</td> 
   <td>int </td> 
   <td>int8</td> 
   <td>int16</td> 
   <td>uint32</td> 
  </tr> 
  <tr> 
   <td>int32</td> 
   <td>int64</td> 
   <td>iota</td> 
   <td>len</td> 
   <td>make</td> 
   <td>new </td> 
   <td>nil</td> 
   <td>panic</td> 
   <td>uint64</td> 
  </tr> 
  <tr> 
   <td>print</td> 
   <td>println</td> 
   <td>real</td> 
   <td>recover</td> 
   <td>string</td> 
   <td>true </td> 
   <td>uint</td> 
   <td>uint8</td> 
   <td>uintptr</td> 
  </tr> 
 </tbody> 
</table>

## 7. Data type ##

*  boolean,default true or false.
 *  int,float32,float64,plural.
 *  string,default encode by utf-8.
 *  extend type:
    
     *  Pointer
     *  Array
     *  Struct
     *  Channel
     *  Function
     *  Slice
     *  Interface
     *  Map

[here]: https://golang.org/dl/