设计一个求结点x在二叉树中的双亲结点算法。
typedef struct node {datatype data; struct node
*lchild,*rchild;} bitree;
bitree *q[20]; int r=0,f=0,flag=0;
void preorder(bitree *bt, char x)
{
if (bt!=0 && flag==0)
if (bt->data==x) { flag=1; return;}
else {r=(r+1)% 20; q[r]=bt; preorder(bt->lchild,x);
preorder(bt->rchild,x); }
}
void parent(bitree *bt,char x)
{
int i;
preorder(bt,x);
for(i=f+1; i<=r; i++) if (q[i]->lchild->data==x ||
q[i]->rchild->data) break;
if (flag==0) printf("not found x\n");
else if (i<=r) printf("%c",bt->data); else
printf("not parent");
}
