JuniorTheoryOccasional

What does the program print?

package main

import "fmt"

func count(n int) {
    if n > 0 {
        fmt.Print(n)
        count(n - 1)
        fmt.Print(n)
    }
}
func main() { count(3) }

321123

Expecting 321: the line after the recursive call still runs, once that call returns, so each count prints its n twice.
Expecting 123321 or 321321: the deepest call finishes first, so the second prints come back in reverse order: 1, 2, 3.

What error or panic do you get when a Go recursion exhausts the stack?
How does the goroutine stack growing on demand differ from a fixed C stack?

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JuniorTheoryOccasional

What does the program print?

package main

import "fmt"

func count(n int) {
    if n > 0 {
        fmt.Print(n)
        count(n - 1)
        fmt.Print(n)
    }
}
func main() { count(3) }

321123

Expecting 321: the line after the recursive call still runs, once that call returns, so each count prints its n twice.
Expecting 123321 or 321321: the deepest call finishes first, so the second prints come back in reverse order: 1, 2, 3.

What error or panic do you get when a Go recursion exhausts the stack?
How does the goroutine stack growing on demand differ from a fixed C stack?

Back to questions Open topic in roadmap →Answer it yourself — Quiz