Scala recursive function

a recursive function

A technique for implementing loops in functional programming.

Example: Calculate n!

def factorial (n:Int):Int = 

  if (n<=0) 1

  else n * factorial(n-1)

 

Two-tail recursive function

All recursive forms of calls in a tail-recursive function occur at the end of the function.

When the compiler detects that a function call is tail recursive, it overwrites the current active record instead of creating a new one on the stack.

 

three code

1. package test_first
3. object tailrec extendsApp{
4. @annotation.tailrec
5. def factorial(n:Int,m:Int):Int=
6. if(n<=0) m
7. else factorial(n-1,m*n)
9. println(factorial(5,1))
10. }

 

Four running results

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