我已阅读有关此问题的其他帖子。当我改变顶线时:
typedef char Key_type;
到
typedef string Key_type;
我在p->key[1] = x;
typedef char Key_type; // change this to string and it breaks
typedef struct node_tag{
int count;
Key_type key[maxSize + 1];
struct node_tag *branch[maxSize + 1];
}Node_type;
Node_type *Insert(Key_type newkey, Node_type *root)
{
Key_type x; /* node to be reinserted as new root */
Node_type *xr; /* subtree on right of x */
Node_type *p; /* pointer for temporary use */
Bool pushup; /* Has the height of the tree increased? */
pushup = PushDown(newkey, root, &x, &xr);
if (pushup) { /* Tree grows in height.*/
/* Make a new root: */
p = (Node_type *)malloc(sizeof(Node_type));
p->count = 1;
p->key[1] = x; // memory access error
p->branch[0] = root;
p->branch[1] = xr;
return p;
}
return root;
}
可以做些什么小修改来消除内存访问错误?
答案 0 :(得分:1)
类。使用字符串成员时,您需要执行
p = new Node_type();
而不是
p = (Node_type *)malloc(sizeof(Node_type));
operator new初始化字符串的内部存储器。 malloc函数,不是。
答案 1 :(得分:0)
你没有为你的字符串调用构造函数。另外,养成编写C ++而不是C:
的习惯typedef string Key_type;
struct Node_type{ // don't need to do typedef ...
int count;
Key_type key[maxSize + 1];
Node_type *branch[maxSize + 1];
};
Node_type *Insert(Key_type newkey, Node_type *root)
{
Key_type x; /* node to be reinserted as new root */
Node_type *xr; /* subtree on right of x */
Node_type *p; /* pointer for temporary use */
Bool pushup; /* Has the height of the tree increased? */
pushup = PushDown(newkey, root, &x, &xr);
if (pushup) { /* Tree grows in height.*/
/* Make a new root: */
p = new Node_type;
p->count = 1;
p->key[1] = x; // memory access error
p->branch[0] = root;
p->branch[1] = xr;
return p;
}
return root;
}
如果您没有为结构提供ctor,编译器将为您创建一个(以及dtor)。