我已经使用Stack以迭代方式编写了一个二进制搜索树的Inorder遍历程序。但是，它正在中止，并显示以下消息：
*** glibc detected *** ./a.out: double free or corruption (fasttop): 0x096c60d8 ***
======= Backtrace: =========
/lib/i386-linux-gnu/libc.so.6(+0x6cbe1)[0x63fbe1]
/lib/i386-linux-gnu/libc.so.6(+0x6e50b)[0x64150b]
/lib/i386-linux-gnu/libc.so.6(cfree+0x6d)[0x64469d]
./a.out[0x804854d]
./a.out[0x80486b4]
./a.out[0x80487d9]
/lib/i386-linux-gnu/libc.so.6(__libc_start_main+0xe7)[0x5e9e37]
./a.out[0x80483c1]
======= Memory map: ========
005d3000-0072f000 r-xp 00000000 08:01 802619 /lib/i386-linux-gnu/libc-2.13.so
0072f000-00731000 r--p 0015c000 08:01 802619 /lib/i386-linux-gnu/libc-2.13.so
00731000-00732000 rw-p 0015e000 08:01 802619 /lib/i386-linux-gnu/libc-2.13.so
00732000-00735000 rw-p 00000000 00:00 0
0076c000-00788000 r-xp 00000000 08:01 802616 /lib/i386-linux-gnu/ld-2.13.so
00788000-00789000 r--p 0001b000 08:01 802616 /lib/i386-linux-gnu/ld-2.13.so
00789000-0078a000 rw-p 0001c000 08:01 802616 /lib/i386-linux-gnu/ld-2.13.so
00c03000-00c1d000 r-xp 00000000 08:01 787452 /lib/i386-linux-gnu/libgcc_s.so.1
00c1d000-00c1e000 r--p 00019000 08:01 787452 /lib/i386-linux-gnu/libgcc_s.so.1
00c1e000-00c1f000 rw-p 0001a000 08:01 787452 /lib/i386-linux-gnu/libgcc_s.so.1
00d02000-00d03000 r-xp 00000000 00:00 0 [vdso]
08048000-08049000 r-xp 00000000 08:01 802400 /home/akash/Code/Data_Structures /Trees /a.out
08049000-0804a000 r--p 00000000 08:01 802400 /home/akash/Code/Data_Structures/Trees/a.out
0804a000-0804b000 rw-p 00001000 08:01 802400 /home/akash/Code/Data_Structures/Trees/a.out
096c6000-096e7000 rw-p 00000000 00:00 0 [heap]
b7700000-b7721000 rw-p 00000000 00:00 0
b7721000-b7800000 ---p 00000000 00:00 0
b78b2000-b78b3000 rw-p 00000000 00:00 0
b78c0000-b78c3000 rw-p 00000000 00:00 0
bfd80000-bfda1000 rw-p 00000000 00:00 0 [stack]
2Aborted
这是我写的代码：
typedef struct node
{
struct node *left;
int data;
struct node *right;
} bTree;
typedef struct stack
{
bTree *tPtr;
struct stack *next;
} stack;
void Push_Stack (stack **sPtr , bTree *tPtrRef)
{
if((*sPtr) == NULL)
{
(*sPtr) = (stack *)malloc(sizeof(stack));
(*sPtr)->tPtr = tPtrRef;
(*sPtr)->next = NULL;
return;
}
else
{
stack *temp = *sPtr;
stack *s;
while((*sPtr)->next != NULL)
{
(*sPtr) = (*sPtr)->next;
}
s = (stack *)malloc(sizeof(stack));
s->tPtr = tPtrRef;
s->next = NULL;
(*sPtr)->next = s;
(*sPtr) = temp;
return;
}
}
bTree *Pop_Stack (stack **sPtr)
{
if((*sPtr) == NULL)
printf("\n Underflow");
else
{
bTree *temp;
stack *s = NULL;
stack *tempPtr = (*sPtr);
while((*sPtr)->next != NULL)
(*sPtr) = (*sPtr)->next;
temp = ((*sPtr)->tPtr);
s = (*sPtr);
free(s);
s = NULL;
(*sPtr) = tempPtr;
return temp;
}
}
void Process_BTreeNode (bTree *ptr)
{
printf("%d",(ptr->data));
}
int IsEmpty_Stack (stack *sPtr)
{
if(sPtr == NULL)
return 0;
else
return 1;
}
void Inorder_BTree_Itr (bTree *rootRef)
{
bTree *tempRoot = rootRef;
stack *tempStack = NULL;
int isDone = 1;
while(isDone)
{
while(tempRoot)
{
Push_Stack (&tempStack , tempRoot);
tempRoot = tempRoot->left;
}
if(IsEmpty_Stack(tempStack))
{
bTree *temp = Pop_Stack (&tempStack);
Process_BTreeNode (temp);
tempRoot = temp->right;
}
else
isDone = 0;
}
}
int main()
{
bTree *head = NULL;
Insert_BTree (&head , 10);
Insert_BTree (&head , 8);
Insert_BTree (&head , 13);
Insert_BTree (&head , 4);
Insert_BTree (&head , 9);
Insert_BTree (&head , 15);
Insert_BTree (&head , 18);
Insert_BTree (&head , 11);
Insert_BTree (&head , 2);
Insert_BTree (&head , 5);
/*Inorder_BTree_Rec (head);*/ //Checked the Insert_Btree func using Recursive Preorder
printf("\n");
Inorder_BTree_Itr(head);
return 0;
}
我尝试使用Valgrind来查找内存损坏的地方，但我无法分析Valgrind日志：
==26857== ERROR SUMMARY: 89088 errors from 3 contexts (suppressed: 11 from 6)
==26857==
==26857== 29696 errors in context 1 of 3:
==26857== Invalid free() / delete / delete[]
==26857== at 0x4025BF0: free (vg_replace_malloc.c:366)
==26857== by 0x804854C: Pop_Stack (BinaryTree.c:59)
==26857== by 0x80486B3: Inorder_BTree_Itr (BinaryTree.c:133)
==26857== by 0x80487D8: main (BinaryTree.c:159)
==26857== Address 0x419e350 is 0 bytes inside a block of size 8 free'd
==26857== at 0x4025BF0: free (vg_replace_malloc.c:366)
==26857== by 0x804854C: Pop_Stack (BinaryTree.c:59)
==26857== by 0x80486B3: Inorder_BTree_Itr (BinaryTree.c:133)
==26857== by 0x80487D8: main (BinaryTree.c:159)
==26857==
==26857==
==26857== 29696 errors in context 2 of 3:
==26857== Invalid read of size 4
==26857== at 0x8048535: Pop_Stack (BinaryTree.c:57)
==26857== by 0x80486B3: Inorder_BTree_Itr (BinaryTree.c:133)
==26857== by 0x80487D8: main (BinaryTree.c:159)
==26857== Address 0x419e350 is 0 bytes inside a block of size 8 free'd
==26857== at 0x4025BF0: free (vg_replace_malloc.c:366)
==26857== by 0x804854C: Pop_Stack (BinaryTree.c:59)
==26857== by 0x80486B3: Inorder_BTree_Itr (BinaryTree.c:133)
==26857== by 0x80487D8: main (BinaryTree.c:159)
==26857==
==26857==
==26857== 29696 errors in context 3 of 3:
==26857== Invalid read of size 4
==26857== at 0x8048529: Pop_Stack (BinaryTree.c:55)
==26857== by 0x80486B3: Inorder_BTree_Itr (BinaryTree.c:133)
==26857== by 0x80487D8: main (BinaryTree.c:159)
==26857== Address 0x419e354 is 4 bytes inside a block of size 8 free'd
==26857== at 0x4025BF0: free (vg_replace_malloc.c:366)
==26857== by 0x804854C: Pop_Stack (BinaryTree.c:59)
==26857== by 0x80486B3: Inorder_BTree_Itr (BinaryTree.c:133)
==26857== by 0x80487D8: main (BinaryTree.c:159)
==26857==
--26857--
--26857-- used_suppression: 11 U1004-ARM-_dl_relocate_object
==26857==
==26857== ERROR SUMMARY: 89088 errors from 3 contexts (suppressed: 11 from 6)
有人可以给我任何关于如何分析Memory Map或Valgrind日志的指示，以便我可以调试此错误。感谢。
答案 0 :(得分：1)
while((*sPtr)->next != NULL)
(*sPtr) = (*sPtr)->next;
temp = ((*sPtr)->tPtr);
s = (*sPtr);
free(s);
在上面的链接列表操作中，您删除了最后一个元素，但是您没有存储被释放的元素的下一个元素。 在链接列表中删除时，还应保留前一个指针。您可以尝试以下方式：
stack *prev = NULL;
while((*sPtr)->next != NULL) {
prev = *sPtr;
(*sPtr) = (*sPtr)->next;
}
if (prev) {
prev->next = NULL;
}