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：
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
|
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？？？
有错误提示，显示：cannot fallthrough final case in switch
fallthrough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。
|
1
2
3
4
5
6
7
8
9
10
11
12
13
|
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：
|
1
2
3
4
5
6
7
8
9
10
11
12
13
|
s := "abcd" switch s[3] { 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：
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服务器之家。如有错误或未考虑完全的地方，望不吝赐教。
原文链接：https://www.cnblogs.com/zsy/p/6741902.html
