Traverse nodes at p ' s ▁ level ▁ ▁ and ▁ find ▁ and ▁ return ▁ the ▁ first ▁ ▁ ▁ node ' s first child
while ( temp != NULL ) { if ( temp -> left != NULL ) return temp -> left ; if ( temp -> right != NULL ) return temp -> right ; temp = temp -> nextRight ; }