package main

import (
    "fmt"
    "go_study/version"
)

var (
    s1 string = "hello world1"
    s2 string = "hello world2"
)

// TIP <p>To run your code, right-click the code and select <b>Run</b>.</p> <p>Alternatively, click
// the <icon src="AllIcons.Actions.Execute"/> icon in the gutter and select the <b>Run</b> menu item from here.</p>
func main() {
    //TIP <p>Press <shortcut actionId="ShowIntentionActions"/> when your caret is at the underlined text
    // to see how GoLand suggests fixing the warning.</p><p>Alternatively, if available, click the lightbulb to view possible fixes.</p>
    s := "gopher"
    s = "tt"
    fmt.Printf("Hello and welcome, %s!\n", s)

    for i := 1; i <= 5; i++ {
        //TIP <p>To start your debugging session, right-click your code in the editor and select the Debug option.</p> <p>We have set one <icon src="AllIcons.Debugger.Db_set_breakpoint"/> breakpoint
        // for you, but you can always add more by pressing <shortcut actionId="ToggleLineBreakpoint"/>.</p>
        fmt.Println("i =", 100/i)
    }
    var rtes string = "ddd"
    var a1, a2 = 3, 4
    fmt.Println("版本号:", version.Version)
    fmt.Printf("%p, %p", &a1, &a2, rtes)
    hello()
}

func hello() {
    fmt.Println("Hello World")
}

package main

import "fmt"

func main() {

    fmt.Println("Hello World", "你好")
    fmt.Printf("%c\n", 'a')
    fmt.Printf("%s\n", "你好")     // 字符串
    fmt.Printf("%d\n", 3)        // 整数
    fmt.Printf("%.2f\n", 3.1459) //保留两位小数 3.15
    var t int32 = '中'
    fmt.Printf("%c\n", t)

    //rune 是 Go 语言中的 字符类型，本质上是 int32，用于表示一个 Unicode 码点（code point）。
    var t2 rune = '中'
    fmt.Printf("%c\n", t2)

    fmt.Printf("%c -> %U\n", 'A', 'A') // A -> U+0041
    fmt.Printf("%c -> %U\n", '你', '你') // 你 -> U+4F60

    //for...range 会自动把 string 拆成 rune 单位，而不是 byte！

    str := "你好Go"
    runes := []rune(str)       //可以算出算符数
    fmt.Println(len(str))      // 字节数（UTF-8）：8
    fmt.Println(len(runes))    // 字符数（rune）：4
    fmt.Println(string(runes)) // 还能转回字符串
    //UTF-8 下：1个中文字符占 3个字节，但在 Go 中用 1 个 rune 表示（int32）。.

    var tmp = 133
    fmt.Printf("%p\n", &tmp) //输出0xf4552890070

    fmt.Printf("%T, %T, %T\n", 3.14159, "字符", &tmp) //类型 float64, string, *int

    fmt.Printf("%v,%v,%v,%v, %v\n", "你好", "", 123, tmp, &tmp)      //输出原始数据 你好,,123,133, 0x11cb60b220e0
    fmt.Printf("%#v,%#v,%#v,%#v, %#v\n", "你好", "", 123, tmp, &tmp) //输出 "你好","",123,133, (*int)(0x15767fb160e0)
    fmt.Printf("请输入你名字:\n")
    var name string
    _, err := fmt.Scan(&name) //返回的第一个值不使用, 用_代替
    if err != nil {
        return
    }
    fmt.Println("请输入年龄:")
    var age int
    _, err = fmt.Scan(&age)
    if err != nil {
        return
    }

    fmt.Printf("名字:%s, 年龄:%d\n", name, age)
}

package main

import (
    "fmt"
    "reflect"
    "strings"
    "unsafe"
)

/*
*
1.整数型
2.浮点型
3.复数
4.布尔
5.字符串
*/
func main() {
    var n1 int = 100 //int在64位系统中为64
    size := unsafe.Sizeof(n1)
    fmt.Printf("n1 的类型 %T, 大小为:%d\n", n1, size)            //n1 的类型 int, 大小为:8
    fmt.Printf("rune类型的大小为: %d\n", unsafe.Sizeof(rune(0))) //rune固定为32位 rune类型的大小为: 4
    fmt.Printf("byte类型的大小为: %d\n", unsafe.Sizeof(byte(0))) //byte类型的大小为: 1
    var f interface{} = 3.14
    fmt.Printf("f的类型是%T\n", f)
    fmt.Println("f的类型是", reflect.TypeOf(f))
    fmt.Println("f的类型名是:", reflect.TypeOf(f).Name())
    var f2 interface{} = []int{3, 4, 5}
    fmt.Print("f2的类型是:", reflect.TypeOf(f2))
    var f3 interface{} = map[string]int{"a": 1, "b": 2}
    fmt.Println("f3的类型是", reflect.TypeOf(f3))
    fmt.Println("hello '' haha''")
    fmt.Println(`
        可换行的
        数据
    `)
    var zero int
    var float float32
    fmt.Println(zero, float)

    var sb strings.Builder
    for i := 0; i < 10; i++ {
        sb.WriteString("hello world\n")
    }
    fmt.Println(sb.String())
}