后端程序员之路 51、A Tour of Go-1

# A Tour of Go
    - go get golang.org/x/tour/gotour
    - https://tour.golang.org/
    
# welcome
    - fmt.Println("The time is", time.Now())

# basic
    - Packages && Imports
        - package main
        - import (    "fmt"    "math" )
        - fmt.Println("My favorite number is", rand.Intn(10))
        - fmt.Println(math.Pi)
    - Functions
        - func add(x int, y int) int {
        - func add(x, y int) int {
        - Multiple results - func swap(x, y string) (string, string) {
        - Named return values - func split(sum int) (x, y int) {
    - Variables
        - var c, python, java bool
        - var c, python, java = true, false, "no!"
        - Short variable declarations - k := 3
        - bool、string、int8 uint16 uintptr、byte（uint8）、rune（int32）、float32 float64、complex64 complex128
        - Zero values
            - Variables declared without an explicit initial value are given their zero value.
            - 0 for numeric types
            - false for the boolean type
            - "" (the empty string) for strings
    - Type conversions
        - i := 42
        - f := float64(i)
        - u := uint(f)
    - Constants
        - const World = "世界"
        - const ( ... )