package main
import (  
        "fmt"
  "math"
  )

var xxx = "nimeide"
func main() { 
        /* my first project */
  fmt.Println("Hello World!") 
  /*x := 10;*/
  for i :=1; i<=9; i++ {   
      for j :=1; j<=i; j++ {     
              /*fmt.Println(i+"*"+j+"="+i*j)*/
      fmt.Print(i*j)
    }
    fmt.Println()
  }
  fmt.Println("==========注释========") 
  // 单行注释
  /*
    你米的
    多行
    注释
  */
  fmt.Println("变量的定义：")
  var age int = 9
  fmt.Println(age)
  var str string = "this is a string word"
  fmt.Println(str)  
  // 先声明变量在进行赋值
  var s2 string
  s2 = "another string word"


  // 直接赋值，让Go语言推断变量类型
  var s3 = "others words"

  // 直接赋值的快捷方式(:=定义变量的方式只能用在函数内部，即 只能定义局部变量)
  s4 := "the last word"
  fmt.Println(s2+"\n"+s3+"\t"+s4)
  xxx = "womeide hh"
  fmt.Println(xxx)
  changeValue()
  fmt.Println(xxx)

  var a float64 = 32.12
  fmt.Println(a)
  fmt.Println(int(a))

  fmt.Println("常量的定义：") 
  const s5 string = "nininininnni"
  fmt.Println("常量：" + s5)
  // s5 = "ww"  
  // 常量不能重新赋值  cannot assign to s5

  fmt.Println("计算圆的面积：")
  var radius float64 = 10
  var area = math.Pow(radius,2) * math.Pi
  fmt.Println(area)

  fmt.Println("批量定义变量和常量")
  var (
    x1= "22"
    x2 = 32
    x3 = true
  ) 
  const (
    x4 = "mi"
    x5 = 321.3
    x6 = false
  )

}

func changeValue() {
  xxx = "new xxx"
}