【基本分类】

go语言的数据类型分四大类

    基础类型    数字 number 字符串string 布尔boolean
    聚合类型    数组 array   结构体struct
    引用类型    指针pointer  slice  map function channel
    接口类型    interface

【基础类型】

  基础类型大致可分3类

  数值类：整型（有无符号）、浮点型、复数

  布尔型： true  false

  字符串

【类型定义】

 各个类型的定义、取值范围以源码 builtin.go为准

无符号整型主要有：uint8   uint16    uint32   uint64

 22 // uint8 is the set of all unsigned 8-bit integers.
 23 // Range: 0 through 255.
 24 type uint8 uint8
 25 
 26 // uint16 is the set of all unsigned 16-bit integers.
 27 // Range: 0 through 65535.
 28 type uint16 uint16
 29 
 30 // uint32 is the set of all unsigned 32-bit integers.
 31 // Range: 0 through 4294967295.
 32 type uint32 uint32
 33 
 34 // uint64 is the set of all unsigned 64-bit integers.
 35 // Range: 0 through 18446744073709551615.
 36 type uint64 uint64

有符号整型主要有：int8   int16     int32    int64

 38 // int8 is the set of all signed 8-bit integers.
 39 // Range: -128 through 127.
 40 type int8 int8
 41 
 42 // int16 is the set of all signed 16-bit integers.
 43 // Range: -32768 through 32767.
 44 type int16 int16
 45 
 46 // int32 is the set of all signed 32-bit integers.
 47 // Range: -2147483648 through 2147483647.
 48 type int32 int32
 49 
 50 // int64 is the set of all signed 64-bit integers.
 51 // Range: -9223372036854775808 through 9223372036854775807.
 52 type int64 int64

浮点型有两类，float32  float64

54 // float32 is the set of all IEEE-754 32-bit floating-point numbers.
 55 type float32 float32
 56 
 57 // float64 is the set of all IEEE-754 64-bit floating-point numbers.
 58 type float64 float64

复数

 60 // complex64 is the set of all complex numbers with float32 real and
 61 // imaginary parts.
 62 type complex64 complex64
 63 
 64 // complex128 is the set of all complex numbers with float64 real and
 65 // imaginary parts.
 66 type complex128 complex128

布尔类型

 13 // bool is the set of boolean values, true and false.
 14 type bool bool
 15 
 16 // true and false are the two untyped boolean values.
 17 const (
 18         true  = 0 == 0 // Untyped bool.
 19         false = 0 != 0 // Untyped bool.
 20 )

字符串

字符串值无法改变：字符串值 本身所包含的字节序列 永不可变。即 字符串内部的数据不允许修改

不可变 意味着 两个字符串能安全的共用 同一段底层内存，使得 复制任何长度 字符串的开销都很低廉

 68 // string is the set of all strings of 8-bit bytes, conventionally but not
 69 // necessarily representing UTF-8-encoded text. A string may be empty, but
 70 // not nil. Values of string type are immutable.
 71 type string string

【类型转换】

    对于每种类型T ，如果可以转换， 操作T（x） 会把 x的值 转换成类型T
    整型与浮点型的相互转换  可能会改变值 或者损失精度