go语言中fallthrough用法

switch sExpr {case expr1:    some instructionscase expr2:    some other instructionscase expr3:    some other instructionsdefault:    other code}

sExpr和expr1、expr2、expr3的类型必须一致。Go的switch非常灵活，表达式不必是常量或整数，执行的过程从上至下，直到找到匹配项；而如果switch没有表达式，它会匹配true。 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，fallthrough不会判断下一条case的expr结果是否为true。

http://play.golang.org/p/LySjbnt53q

package mainimport "fmt"func main() {    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")    case false:            fmt.Println("The integer was <= 8")            fallthrough    default:            fmt.Println("default case")    }}

运行结果：

The integer was <= 5The integer was <= 6The integer was <= 7

从本例可以看出：switch人第一个expr为true的case开始执行，如果case带有fallthrough，程序会继续执行下一条case,不会再判断下一条case的expr,如果之后的case都有fallthrough,default出会被执行。