Go Part I: Variables, constants, and enumeration types

This is a creation in Article, where the information may have evolved or changed.

GoIn the first article, I will refine the basic points that are used frequently, and for those children who have just begun to get started Go , the foundation is not solid enough to refer to Go the basic usage of this article for quick review.

Series Finishing:

• Go Part II: Branch statements, functions

If you are interested in the Go language itself, you can read my translation of the advantages, disadvantages and repulsive design of the go language.

Variable definition

// 默认为零值var a stringvar b intvar a, b string // 声明变量值var e string = "abc"// 变量属于同一类型，可只写一次类型var c, d int = 3, 4// 推论类型var f, g, h, i = 3, 4, true, "def"f, g, h, i := 3, 4, true, "def"// 括号写法var (    aa = 3    ss = "kkk"    bb = true)

Built-in variable type

• BOOL, string
• (u) int, (U) int8, (U) int16, (U) Int32, (U) Int64, uintptr
• Byte, Rune
• float32, Float64, complex64, complex128

Complex is a plural type

// 不用1i，程序会将 i 识别为变量fmt.Printf("%.3f\n", cmplx.Exp(1i*math.Pi) + 1)

Forcing type conversions

var a, b int = 3, 4// math.Sqrt 参数和返回值都是  float64c := int(math.Sqrt(float64(a *a + b * b)))

Definition of constants

const a, b = 3, 4const (    filename = "abc.txt"    a, b = 3, 4)// const 数值可以作为任意的类型使用,所以此处 a, b变量不需要手动转换为 float64c := int(mant.Sqrt(a*a + b*b))

Self-Increment enumeration type

const (    javascript = iota    c    python    _    php)const (    b = 1 << (10 * iota)    kb    mb    gb    tb    pb)