Gin is a web framework written in Go (Golang). It features a martini-like API with performance that is up to 40 times faster thanks to httprouter. If you need performance and good productivity, you will love Gin.
https://github.com/gin-gonic/gin
MUST be declared before using it
Order of declaring a variable in your code, here is an example of the declared variable unrecognized by fmt.Println() statement. The GO compiler (go build) took each line (reading from top to bottom) of the source code. In this case, you have a variable name odometer use but not data type and memory address defined. The compilation has failed or IDE for GO may prompt it as a problem.
// Variable declared but return error message
// when compile (go build)
//
func main() {
fmt.Println(odometer)
var odometer int
}
// Corrected code compile without error and
// execution of code will return a value
func main() {
var odometer int
fmt.Println(odometer)
}
MUST declare before using it
Declaration Syntax
var variable_name type
var odometer int
Naming Rules (variable names and function names)
Note: If the above rule is not followed, IDE for Go will prompt for errors, and Go run compilation will fail.
By convention, one-method interfaces are named by the method name plus an -er suffix.
type Greetinger interface {
Greeting() string
}It start with the keyword “type” follow by the interface name (ended with -er). Begin of a block of code symbol “{“, the function name (eg. Greeting() function and return a string ). One or more than one function can be added here then is often called a method set and ending of a block of code “}”.
// https://golang.org/pkg/os/#FileInfo
type FileInfo interface {
Name() string // base name of the file
Size() int64 // length in bytes for regular files; system-dependent for others
Mode() FileMode // file mode bits
ModTime() time.Time // modification time
IsDir() bool // abbreviation for Mode().IsDir()
Sys() interface{} // underlying data source (can return nil)
}In the above OS package, has FileInfo interface contains the following method sets
Official Go download page, this link gives you more option to choose from OS platform and OS architecture x86-64 build. And you can use the go build command parameter to building a binary for an application that can run for CPU of x86 (386) and x86-64.
Install
Open the MSI file you downloaded and follow the prompts to install Go. The default folder used is C:/go. Or choose any folder that Windows 10 security may not ask for an administrator password for install programs/files using that folder path.
System Environment variable created by MSI installer
GOPATH C:\Users\loginname\go
Note: loginname is the user name to Window login
PATH C:\Go\bin
Verify
Launch a windows terminal, type go version
go version go1.15.6 windows/amd64 output confirmed go installation has been successful. Otherwise, use the Windows Control panel app -> Programs find go1.15.6 has been program has been installed.
Troubleshooting
Google, Go forum, and Stackoverflow for assistance.
package main
import "fmt"
func main() {
kvs := map[string]string{"1":"shan kuo","2":"Hoi Leng","3":"Choi Yan","4":"Evelyn Chan"}
for k, v := range kvs {
fmt.Printf("%s -> %s\n",k,v)
}
}https://repl.it/join/gdzplzna-shankuo
go build
./main
1 -> shan kuo
2 -> Hoi Leng
3 -> Choi Yan
4 -> Evelyn Chan
package main
import "fmt"
func main() {
names := []string{"Shank Kuo","Hoi Leng","Choi Yan","Evelyn Chan"}
for i:=0; i < len(names); i++ {
fmt.Println(names[i])
}
}https://repl.it/@shankuo/LoopArraySlice
go version go1.14 linux/amd64
go run main.go
Shank Kuo
Hoi Leng
Choi Yan
Evelyn Chan
https://play.golang.org/p/3HpTAxoPC6l
// in Go Data Structures and algorithms book
package main
// importing fmt package
import (
"fmt"
)
// main method
func main() {
var rows int
var cols int
rows = 7
cols = 9
// rows := 7
// cols := 9
var twodslices = make([][]int, rows)
var i int
for i = range twodslices {
twodslices[i] = make([]int, cols)
}
fmt.Println(twodslices)
}https://play.golang.org/p/F5MTsF_Z1J1
// in Go Data Structures and algorithms book
package main
// importing fmt package
import (
"fmt"
)
// main method
func main() {
var TwoDArray [8][8]int
TwoDArray[3][6] = 18
TwoDArray[7][4] = 3
fmt.Println(TwoDArray)
}