在 Go 中递归遍历文件和文件夹 - 无法理解递归是如何发生的

Question

示例1.（我可以理解这段代码中的递归，findFactorial里面调用了函数）package mainimport "fmt"var repeated = 0func main() {    fmt.Println("Answer :",findFactorial(3))}func findFactorial(x int) int {    repeated ++    fmt.Printf("Repeating.., Now repeated %v times\n",repeated)    if x == 0 {        return 1    }    return x * findFactorial(x-1) // it is evident that this same function is calling again }输出go run .\factorial.go     Repeating.., Now repeated 1 timesRepeating.., Now repeated 2 timesRepeating.., Now repeated 3 timesRepeating.., Now repeated 4 timesAnswer : 6示例 2.（这里我无法理解，递归是如何发生的）package mainimport (    "fmt"    "log"    "os"    "path/filepath")var repeated = 0func main() {    iterate("../../../../TEMP")}func iterate(path string) {    fmt.Println("path",path)    filepath.Walk(path, func(x string, info os.FileInfo, err error) error {        repeated ++        fmt.Printf("Repeating.., Now repeated %v times\n",repeated)        if err != nil {            log.Fatalf(err.Error())        }        fmt.Printf("File Name: %s\n", info.Name())        return nil    })}输出go run .\filepathwalktu.gopath ../../../../TEMPRepeating.., Now repeated 1 timesFile Name: TEMPRepeating.., Now repeated 2 timesFile Name: PNR.pngRepeating.., Now repeated 3 timesFile Name: tkt.pngRepeating.., Now repeated 4 timesFile Name: understand this.txt

Answer 1

第二个例子不是递归（至少从用户的角度来看）。您只需使用带有回调的 API。filepath.Walk是一个标准库函数，它将函数作为参数。在这个例子中，回调是一个闭包或匿名定义的函数。当filepath.Walk找到新的文件系统条目时调用该回调。在内部filepath.Walk可能会或可能不会实现为递归。

以防万一这是一个使用函数作为与递归无关的参数的示例：

func foo(cb func(int)) {

    // cb is a function that passed as an argument 

    // it is called 3 times without any recursion

    cb(0)

    cb(1)

    cb(2)

}

func main() {

    foo(func(i int) {

        fmt.Println("hello,", i)

    })

}