运维开发网

go语言中fallthrough的用法说明

运维开发网 https://www.qedev.com 2022-04-01 02:28 出处:网络 作者: 腾信@迪克猪
fallthrough:Go里面switch默认相当于每个case最后带有break,匹配成功后不会自动向下执行其他case,而是跳出整个switch,但是可以使用fallthrough强制执行后面...

fallthrough:Go里面switch默认相当于每个case最后带有break,匹配成功后不会自动向下执行其他case,而是跳出整个switch, 但是可以使用fallthrough强制执行后面的case代码。

示例程序1:

switch {
    case false:
        fmt.Println("The integer was <= 4")
        fallthrough
    case true:
        fmt.Println("The integer was <= 5")
        fallthrough
    case false:
        fmt.Println("The integer was <= 6")
        fallthrough
    case true:
        fmt.Println("The integer was <= 7")
        fallthrough
    case false:
        fmt.Println("The integer was <= 8")
    default:
        fmt.Println("default case")
    }

输出结果:

The integer was <= 5

The integer was <= 6

The integer was <= 7

The integer was <= 8

问题:是否在switch最后一个分支使用fallthrough???

go语言中fallthrough的用法说明

有错误提示,显示:cannot fallthrough final case in switch

fallthro编程客栈ugh不能用在switch的最后一个分支。

示例程序2:

上述示例是true、false常量进行分支判断,看如下变量示例。

s := "abcd"
    switch s[1] {
    case 'a':
        fmt.Println("The integer was <= 4")
        fallthrough
    case 'b':
        fmt.Println("The integer was <= 5")
        fallthrough
    case 'c':
        fmt.Println("The integer was <= 6")
    default:
        fmt.Println("default case")
    }

输出结果如下:

The integer was <= 5

The integer was <= 6

更改为:

s := "abcd"
    switch s[3] {
    case 'a':
        fmt.Println("The integer was <= 4")
        fallthrough
  编程客栈  case 'b':
        fmt.Println("The integer was <= 5")
        fallthrough
    case 'c':
        fm编程客栈t.Println("The integer was <= 6"编程客栈)
    default:
        fmt.Println("default http://www.cppcns.comcase")
    }

输出:

default case

总结:

switch分支中使用变量进行判断的时,fallthrough正确的分支开始其作用。

补充:【踩坑】golang的fallthrough大坑

加了fallthrough后,会直接运行【紧跟的后一个】case或default语句,不论条件是否满足都会执行,后面的条件并不会再判断了,?

以上为个人经验,希望能给大家一个参考,也希望大家多多支持我们。如有错误或未考虑完全的地方,望不吝赐教。

0

精彩评论

暂无评论...
验证码 换一张
取 消