打印二叉树中和为某一值的路径

输入一个二叉树，查找该树的所有路径（从根结点到叶结点的通路），并返回和（路径上所有结点值的和）为某一指定值的路径。

/////////////二叉树中和为某一值的路径/////////////////////
void FindPath(BinaryTreeNode* pRoot ,int expectedSum ,vector<int>& path ,int currentSum)
{
    if (pRoot == NULL)
    {
        return;
    }
    currentSum += pRoot->m_nValue;
    path.push_back(pRoot->m_nValue);
    //如果是叶子结点，且结点的和等于希望的值，打印出这条路径
    if (currentSum == expectedSum && pRoot->m_pLeft == NULL && pRoot->m_pRight == NULL)
    {
        cout<<"Find a path : ";
        vector<int>::iterator iter = path.begin();
        for (;iter != path.end() ; iter++)
        {
            cout<<*iter<<" ";
        }
        cout<<endl;
    }
    if (pRoot->m_pLeft)
    {
        FindPath(pRoot->m_pLeft ,expectedSum ,path ,currentSum);
    }
    if (pRoot->m_pRight)
    {
        FindPath(pRoot->m_pRight ,expectedSum ,path ,currentSum);
    }
    //currentSum = currentSum - path.back();
    path.pop_back();
}
void FindPath(BinaryTreeNode* pRoot , int expectedSum)//用户接口
{
    if (pRoot == NULL)
    {
        return;
    }
    int currentSum = 0 ;
    vector<int> vec ;
    FindPath(pRoot ,expectedSum ,vec , currentSum );

}