go基本数据类型

package main

import (
	"fmt"
	"os"
	"strings"
	"unsafe"
)

func main() {
	who := "World"
	if len(os.Args) > 1 {
		who = strings.Join(os.Args[1:], " ")
	}
	fmt.Println("Hello", who)

	//定义int,double数据类型
	var ivalue int
	ivalue = 1
	ivalue2 := 2         //类似auto
	var rune_ivalue rune //rune,类似int32
	rune_ivalue = 3
	var dvalue float64
	dvalue = 0.123
	fmt.Println("ivalue:", ivalue, ",ivalue2:", ivalue2, ",rune_ivalue:", rune_ivalue, ",dvalue:", dvalue)

	//bool值初始化
	var bvalue bool = true
	fmt.Println("bvalue:", bvalue)

	//数组
	int_arr := []int{1, 2, 3}
	str_arr := []string{"a", "b", "c"}
	fmt.Println("int_arr[2]:", int_arr[2], "str_arr[1:]:", str_arr[1:])

	//字符串相连
	fmt.Println("xiang" + "jie")

	//uintptr,无符号整型，用于存放一个指针
	v1 := uint(1)
	p := &v1
	fmt.Println("uintptr:", *p)

	//unsafe.Pointer是特别定义的一种指针类型（译注：类似C语言中的void类型的指针），它可以包含任意类型变量的地址
	up := (*uint)(unsafe.Pointer(&v1))
	fmt.Println("unsafe.Pointer:", *up)

	var x struct {
		a bool
		b int16
		c []int
	}
	unsafePa := (*bool)(unsafe.Pointer(uintptr(unsafe.Pointer(&x))))
	*unsafePa = true
	unsafePb := (*int16)(unsafe.Pointer(uintptr(unsafe.Pointer(&x)) + unsafe.Offsetof(x.b)))
	*unsafePb = 42
	fmt.Println("x.a:", x.a, "x.b:", x.b)
}

Hello World
ivalue: 1 ,ivalue2: 2 ,rune_ivalue: 3 ,dvalue: 0.123
bvalue: true
int_arr[2]: 3 str_arr[1:]: [b c]
xiangjie
uintptr: 1
unsafe.Pointer: 1
x.a: true x.b: 42

package main

import "fmt"
import "math"

func main() {
	const i = 1
	f := 1.2
	fmt.Println("a", i, f)
	a := "aaa"
	b := "bbb"
	c := a + b
	var d []string
	var e = append(d, a, b)
	fmt.Println(c)
	fmt.Println(e)
	var x = 1.0 / 2
	fmt.Println(x)
	var k = 0 / 2 //没出异常
	fmt.Println(k)
	fmt.Println(math.IsNaN(f))
}

a 1 1.2
aaabbb
[aaa bbb]
0.5
0
false