[英]C - Null pointer issue on AVL tree rotation implementation
我正在C中实现AVL树。我在下面发布了树的旋转角度,以及尝试测试它们时遇到的valgrind错误。
为什么会出现这些错误? 我知道valgrind错误源于我使用空指针的事实,但我无法确切指出我在做什么错。 (我对Valgrind错误行进行了评论)
Tree rotateRight(Tree t)
{
Tree temp = t->L;
t->L=temp->R;
temp->R=t;
temp->height=maximum(heightT(temp->L), heightT(temp->R));
t->height=maximum(heightT(t->L), heightT(t->R));
return t;
}
Tree rotateLeft(Tree t)
{
Tree temp = t->R; //This is line 226
t->R=temp->L;
temp->L=t;
temp->height=maximum(heightT(temp->L), heightT(temp->R));
t->height=maximum(heightT(t->L), heightT(t->R));
return t;
}
Tree rotateLeftRight(Tree t)
{
t->L=rotateLeft(t->L); //Line 235
t=rotateRight(t);
return t;
}
Tree rotateRightLeft(Tree t)
{
t->R=rotateRight(t->R);
t=rotateLeft(t);
return t;
}
Valgrind错误(我在rotateLeft上得到了同样的东西):
==20073== Invalid read of size 8
==20073== at 0x40196F: rotateLeft (bst.c:226)
==20073== by 0x401A11: rotateLeftRight (bst.c:235)
==20073== by 0x4013A9: insertT (bst.c:69)
==20073== by 0x400E77: addin (Spell13.c:96)
==20073== by 0x400CBE: main (Spell13.c:59)
==20073== Address 0x10 is not stack'd, malloc'd or (recently) free'd
==20073==
==20073==
==20073== Process terminating with default action of signal 11 (SIGSEGV)
拿您拥有的代码+错误报告,看起来Tree
看起来像这样:
typedef struct Tree_s
{
struct Tree_s *L;
struct Tree_s *R;
} Tree;
似乎传递给rotateLeftRight
Tree->L
为NULL
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