c++ - Is this function really tail-recursive? -


i read recursion in programming interviews exposed (3rd ed.) present following recursive factorial function:

int factorial(int n){     if (n > 1) { /* recursive case */         return factorial(n-1) * n;     } else {     /* base case */         return 1;     } }

on bottom of same page (page 108) talk tail-recursive functions:

note when value returned recursive call returned, in preceding definition factorial, function tail-recursive.

but case here? last call in function * call, won't stack frame preserved (if don't take compiler optimization account)? tail-recursive?

no, it's not tail-recursive. result being returned factorial(n-1) still has multiplied n, requires factorial(n) regain control (thus mandating call factorial(n-1) call rather jump).

with said, if tail-recursive, compiler still might not tco on it. depends on compiler , optimizations ask do.


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