// 判斷語句
func panduan(a int) {
    if a > 50 {
        fmt.Println("a > 50")
    } else if a < 30 {
        fmt.Println("a < 30")
    } else {
        fmt.Println("a <= 50 and a >= 30")
    }
}
 
func main() {
    panduan(120)
}

//嵌套判斷
func qiantao(b, c uint) {
    if b >= 100 {
        b -= 20
        if c > b {
            fmt.Println("c OK")
        } else {
            fmt.Println("b OK")
        }
    }
}

//switch使用
func test_switch() {
    var a uint = 90
    var result string
    switch a {
    case 90:
        result = "A"
    case 80, 70, 60:
        result = "B"
    default:
        result = "C"
    }
    fmt.Printf("result: %v\n", result)
    switch {
    case a > 90:
        result = "A"
    case a <= 90 && a >= 80:
        result = "B"
    default:
        result = "C"
    }
    fmt.Printf("result: %v\n", result)
 
}

//測試類型switch
func test_type_switch() {
    var x interface{}
    x = 1.0
    switch i := x.(type) {
    case nil:
        fmt.Printf("x type = %T\n", i)
    case bool, string:
        fmt.Printf("x type = bool or string\n")
    case int:
        fmt.Printf("x type = int\n")
    case float64:
        fmt.Printf("x type = float64\n")
    default:
        fmt.Printf("未知\n")
    }
}

// 測試fallthrough
func test_fallthrough() {
    a := 1
    switch {
    case a < 0:
        fmt.Println("1")
        fallthrough
    case a > 0:
        fmt.Println("2")
        fallthrough
    case a < 0:
        fmt.Println("3")
        fallthrough
    case a < 0:
        fmt.Println("4")
    case a > 0:
        fmt.Println("5")
        fallthrough
    case a < 0:
        fmt.Println("6")
        fallthrough
    default:
        fmt.Println("7")
    }
}