Go Language Primer

A Go Environment installation deployment

Chinese go Documentation and installation package: HTTPS://STUDYGOLANG.COM/DL
#windows安装下载软件包 Next Installation Complete
Use the MSI file and follow the prompts to install the Go tool. By default, the Setup program uses the C:\Go directory. The installer should set the directory in the window's PATH environment variable C:\Go\bin . After restarting, open a command prompt to verify that the change is in effect.
Verifying the installation Results
F:\worksp\golangCreate a test.go go file in. Write and save the following code into the test.go file.

package mainimport "fmt"func main() { fmt.Println("Hello, World!")}

Download the installation package using binary mode in the #Linux  extract Add environment variable


Export path= $PATH:/usr/local/go/bin

Second: The first Go program code

" FMT " Func Main () {    var"egrep"    fmt. Printf ("Hell World Welcome Learn go  ", name)}

#以上代码的解释

• If you are compiling the code into an executable program, the package must be main: the beginning of the program
• If it is to compile the code into a library, then the package has no restrictions
• All the code in the Go program should be described in a package
• FMT is a system library FMT in go. Println () can print the output and wrap the FMT. Print () prints FMT. Printf () printing supports formatted output
• If you want to run a program command go run #先编译后执行
• There is only one main function in an executable program
• #注释说明
• Single-line comment//
• Multiline Comment/* */

#执行的结果如下

d:\PROJECT-practice under \src\day01>go Build hellworld.god:\project-class practice \src\day01>hellworld.exehell World Welcome Learn go egrepd:\project-practice \src\day01>go run Hellworld.gohell World Welcome Learn Go egrepd:\project-Class practice \src\ Day01>

Three GO command summary

Go Run program name #先编译后执行  go build  #编译源代码为二进制的文件 under  Windows translated into program name  . EXE Linux translated into executable file go install  /bin/ file directory under    gofmt-w. #将代码格式化   such as: The following code indentation is not very perfect, we can use the command gofmt-w.

Four: Simple introduction to the variable of Go language

Define a variable keyword var

var variable name variable type #如 var name = "Egrep" #切记在go里面 double quotes inside are string types, single quotes are character types they are different.

Defining a variable and assignment can be done in one step by: variable name: = value #如: Name: = "Egrep" can also be var name string = "Egrep" or

var (name = "Egrep" age = 18)

Attention:

The variables that are defined in the go language, or the packages that are referenced, must be used, or they will be error, as shown below

" FMT " Func Main () {    var"egrep"    fmt. Printf ("Hell World Welcome Learn go   ")}

#编译执行的时候报错

d:\PROJECT-Practice \src\day01>go Run Hellworld.go
# command-line-arguments
. \hellworld.go:6:6:name declared and not used

Go Language Primer