递归求二叉树的宽度,二叉树递归求深度如何理解

int TreeDepth(yydzp pRoot){ if(pRoot == NULL) return 0; int nLeft = TreeDepth(pRoot->m_pLeft); int nRight = TreeDepth(pRoot->m_pRight); return (nLeft > nRight) ? (nLeft + 1) : (nRight + 1);}