[函数5-1] bool SearchBtree(BTreeNode* root, ElemKeyType akey, BTreeNode **ptr) {int lw, hi, mid;BTreeNode*p = root;*ptr = NULL;while ( p ) { 1w = 1; hi= (1) ; while (1w <= hi) {mid = (1w + hi)/2;if (p -> K[mid] == akey) { *ptr = p; return TRUE; }else if ( (2) ) hi=mid - 1; else 1w = mid + 1; } *ptr = p; p = (3) ; }return FALSE; }