scala之尾递归优化

@tailrec

object DemoTest extends App {

def getSum2(list: List[Int]): Int = {
@tailrec
def sumHelp(list: List[Int], sum: Int): Int = {
if (list == Nil) sum
else sumHelp(list.tail, sum + list.head)
}
sumHelp(list, 0)
}
@tailrec
def getSum(list:List[Int]):Int = {
if(list == Nil) 0
else list.head + getSum(list.tail)
}
}