go语言逻辑

if

// 简单If例子
    a := 1
    if a == 1 {
        fmt.Println("a = 1")
    } else if a == 2{
        fmt.Println("a = 2")
    }else{
        fmt.Println("a = others ")
  }
// 读取文件
    const filename = "abc1.txt"
    if contents, err :=     ioutil.ReadFile(filename); err != nil{
        fmt.Println(err)
    }else{
        fmt.Printf("%s\n", contents)
    }

switch

    var op = "+"
    switch op {
    case "+":
        fmt.Println("+")
    case "-":
        fmt.Printf("-")
    default:
        panic("unsupported operator:"+ op)
    }

for

    sum := 0
    for i:=1 ; i<100; i++ {
        sum+= i
    }
    fmt.Println(sum)

func convertToBin(n int)  string{
    result := ""
    for ; n>0 ; n/=2  {
        lsb := n%2
        //strconv.Itoa(lsb) 转换字符串
        result = strconv.Itoa(lsb) + result
    }
    return result
}

func main()  {

    fmt.Println(
            convertToBin(5),
            convertToBin(13),
        )
}

//读文件，省略开始和递增条件
func printFile(filename string)  {
    file, err := os.Open(filename)
    if err != nil{
        panic(err)
    }
    scanner := bufio.NewScanner(file)
    for scanner.Scan() {
        fmt.Println(scanner.Text())
    }
}
//死循环
func forver()  {
    for  {
        fmt.Println("abc")
    }
}

func main()  {
    printFile("abc.txt")
    forver()
}