Understanding recursion [closed]

Answer 1

I'll try to explain it with an example.

You know what n! means? If not: http://en.wikipedia.org/wiki/Factorial

3! = 1 * 2 * 3 = 6

here goes some pseudocode

function factorial(n) {
  if (n==0) return 1
  else return (n * factorial(n-1))
}

So let's try it:

factorial(3)

is n 0?

no!

so we dig deeper with our recursion:

3 * factorial(3-1)

3-1 = 2

is 2 == 0?

no!

so we go deeper! 3 * 2 * factorial(2-1) 2-1 = 1

is 1 == 0?

no!

so we go deeper! 3 * 2 * 1 * factorial(1-1) 1-1 = 0

is 0 == 0?

yes!

we have a trivial case

so we have 3 * 2 * 1 * 1 = 6

i hope the helped you