C$++$

Given any positive integer $n,$ define

$f(n)$:$=\{\begin{array}{ccc}\frac{n}{2}& is\text{e}\text{v}\text{e}\text{n}& \\ 3n+1,& nis\text{o}\text{d}\text{d}\text{.}& \end{array}$

The Collatz conjecture states that the sequence

$a_i$:$=\{\begin{array}{cc}n,& i=0\\ f(a_{i-1}),& i>0\end{array}$

eventually reaches $1.$ Write a function int collatzLength $($int $n)$ that

determines the first i for which $a_i=1$ for a given $n.$ For example, when $n=$

$17,$ the sequence $a_i$ begins

$17,52,26,13,40,20,10,5,16,8,4,2,1,$dots

and $a_{12}=1.$ Thus, collatzLength $(17)$ should return $12.$