![](/img/trans.png)
[英]Implementing an AVL tree, but getting seg fault on large data file insertion
[英]AVL Tree Insertion Causes Seg Fault
我一直在嘗試在AVL程序中實現旋轉功能,並且在調用Right Rotate函數時繼續出現段錯誤。 我執行了Valgrind測試,發現3個錯誤:
==23399== 1 errors in context 1 of 3:
==23399== Invalid read of size 4
==23399== at 0x8048C3A: insert (avltree.c:190)
==23399== by 0x80488B6: main (avltree.c:85)
==23399== Address 0x3 is not stack'd, malloc'd or (recently) free'd
==23399==
==23399==
==23399== 1 errors in context 2 of 3:
==23399== Use of uninitialised value of size 4
==23399== at 0x8048C3A: insert (avltree.c:190)
==23399== by 0x80488B6: main (avltree.c:85)
==23399== Uninitialised value was created by a stack allocation
==23399== at 0x8048723: main (avltree.c:42)
==23399==
==23399==
==23399== 1 errors in context 3 of 3:
==23399== Conditional jump or move depends on uninitialised value(s)
==23399== at 0x8048C03: insert (avltree.c:182)
==23399== by 0x80488B6: main (avltree.c:85)
==23399== Uninitialised value was created by a stack allocation
==23399== at 0x8048723: main (avltree.c:42)
它在兩個錯誤中提到存在一個未初始化的值。 我認為這與我交換左右子樹的值有關,但是我似乎無法確切指出出問題的地方。
這是我的“ 右旋轉”功能:
void rightRotate(node * y)
{
/* Assign values */
node *x = y->left;
node *subTree = x->right;
/* Perform rotation */
x->right = y; /* x is now root */
y->left = subTree;
/* Update heights */
y->height = max(height(y->left), height(y->right))+1;
x->height = max(height(x->left), height(x->right))+1;
}
所有插入的方式都是使用Insertion函數:
void insert(node ** tree, node * item)
{
int balanceNum;
/* If no root, item is root */
if(!(*tree)) {
*tree = item;
printf("Root: \n"); /*Every node seems to get printed here */
(*tree)->height = 0;
return;
}
if(strcmp(item->key,(*tree)->key) < 0) {
insert(&(*tree)->left, item);
}
else if(strcmp(item->key,(*tree)->key) > 0) {
insert(&(*tree)->right, item);
}
else if(strcmp(item->key,(*tree)->key) == 0) {
(*tree)->frequency++;
}
/* Update height of ancestor node */
(*tree)->height = max(height((*tree)->left), height((*tree)->right)) + 1;
printf("%s Height: %d\n", (*tree)->key, (*tree)->height);
balanceNum = balance(*tree);
if(balanceNum > 1 && strcmp(item->key,(*tree)->left->key) < 0) {
printf("Right Rotate! Balance: %d with %s\n", balanceNum, item->key);
rightRotate(*tree);
}
}
為了這種特殊情況,我刪除了其余的旋轉功能。 有人可以指出我的旋轉功能可能出問題了嗎?
非常感謝您的任何建議或提示。
編輯:我更新了valgrind發布以包括我的代碼的行號。
這是因為每次插入函數時,都會執行以下代碼:
if(!(*tree)) {
*tree = item;
printf("Root: \n"); /*Every node seems to get printed here */
(*tree)->height = 0;
return;
}
原因是insert()被遞歸調用。
if(strcmp(item->key,(*tree)->key) < 0) {
insert(&(*tree)->left, item);
}
else if(strcmp(item->key,(*tree)->key) > 0) {
insert(&(*tree)->right, item);
}
else if(strcmp(item->key,(*tree)->key) == 0) {
(*tree)->frequency++;
}
&(* tree)-> left可以為NULL。 假設當前樹中只有一個根,則其左和右為NULL指針。 插入似乎將繞過if(!(* tree))。 但是,它將調用insert(&(* tree)-> left,item)或insert(&(* tree)-> right,item),它們兩個都將NULL指針作為其第一個參數。
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.