我正在尝试从数组中制作b树,我想出了这段代码,但是它没有编译,并且给了我这个错误:第42行的“'->”令牌之前的预期非限定ID”:
节点->平衡=右高度-左高度;
这里是完整代码:
#include <iostream>
#include <cstring>
#include <cstdlib>
#include <cmath>
struct node {
node *left;
node *right;
int balance;
int value;
};
node *build_subtree(int *items, int length, void* node_mem, int *height = NULL) {
/*This will give either the middle node or immediately to the right.*/
int root_index = length / 2;
/* Make the node. It will be at the same index in its
memory block as its value. Who needs memory management? */
node *root = (node*)((char*)node_mem + sizeof(node) * root_index);
root->value = *(items + root_index);
/* These values will be used to compute the node balance */
int left_height = 0, right_height = 0;
/* Build the left subtree */
if (root_index > 0) {
root->left = build_subtree(items,
root_index,
node_mem,
&left_height);
}
/* Build the right subtree */
if (root_index < length - 1) {
root->right = build_subtree(items, root_index,
(char*)node_mem + sizeof(node) * root_index,
&right_height);
}
/* Compute the balance and height of the node.
The height is 1 + the greater of the subtrees' heights. */
node->balance = right_height - left_height;
if (height) {
*height = (left_height > right_height ? left_height : right_height) + 1;
}
return root;
}
int main() {
int values[10000000];
for (int i=1; i<=10000000; i++)
values[i] = i;
void *mem = malloc(sizeof(node) * 10000000);
memset(mem, 0, sizeof(node) * 10000000);
node *root = build_subtree(values, 10000000, mem);
}
请帮助D:
node
是一种类型,而不是指针的名称。因此node->balance
在语法上不正确。
节点是一个结构,而不是指针的名称。您要使用balance,它是此结构的变量。因此,您必须使用节点的对象来达到变量平衡,例如root:root-> balance。