我在尝试编译C ++程序时遇到分段错误问题，但不确定问题出在哪里。我怀疑问题在于.find（）.....它可能是迭代器运算符＆lt;和==哪个是find（）的比较器，这是什么问题？我希望有人可以向我指出他们认为问题所在。
以下是test01.cpp的一部分，我运行它来测试代码并使用print语句找出问题所在：
bool confirmEverythingMatches(const btree<long>& testContainer, const set<long>& stableContainer) {
cout << "Confirms the btree and the set "
"contain exactly the same values..." << endl;
for (long i = kMinInteger; i <= kMaxInteger; i++) {
cout << "Start of for-loop to find iterator for comparisons..." << endl;
if (stableContainer.find(i) != stableContainer.end()) {
cout << "can find i (" << i << ") in stableContainer!" << endl;
} else {
cout << "cannot find i (" << i << ") in stableContainer!" << endl;
}
cout << "In between finding i in stable and testContainers..." << endl;
if (testContainer.find(i) != testContainer.end()) {
cout << "can find i (" << i << ") in testContainer!" << endl;
} else {
cout << "cannot find i (" << i << ") in testContainer!" << endl;
}
cout << "Before assigning the find to boolean variables..." << endl;
bool foundInTree = (testContainer.find(i) != testContainer.end());
cout << "testContainer.find(i) != testContainer.end()" << endl;
bool foundInSet = (stableContainer.find(i) != stableContainer.end());
cout << "stableContainer.find(i) != stableContainer.end()" << endl;
if (foundInTree != foundInSet) {
cout << "- btree and set don't contain the same data!" << endl;
cout << "Mismatch at element: " << i << endl;
return false;
} else {cout << "foundInTree == foundInSet!!!" << i << endl;}
}
cout << "- btree checks out just fine." << endl;
return true;
}
} // namespace close
/**
* Codes for testing various bits and pieces. Most of the code is commented out
* you should uncomment it as appropriate.
**/
int main(void) {
// initialise random number generator with 'random' seed
initRandom();
cout << "after initRandom().." << endl;
// insert lots of random numbers and compare with a known correct container
btree<long> testContainer(99);
cout << "after specifying max node elements in testContainer.." << endl;
set<long> stableContainer;
cout << "after constructing stableContainer.." << endl;
insertRandomNumbers(testContainer, stableContainer, 1000000);
cout << "after inserting random numbers into testContainer and for success inserts, also into stableContainer.." << endl;
btree<long> btcpy = testContainer;
cout << "after copy assigning a copy of testContainer to btcopy.." << endl;
confirmEverythingMatches(btcpy, stableContainer);
cout << "after confirming everything internally matches between testContainer and stableContainer.." << endl;
return 0;
}
运行程序时得到的输出（编译时没问题）是：
Confirms the btree and the set contain exactly the same values...
Start of for-loop to find iterator for comparisons...
cannot find i (1000000) in stableContainer!
In between finding i in stable and testContainers...
ASAN:DEADLYSIGNAL
=================================================================
==7345==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000018 (pc 0x000108d132a8 bp 0x000000000000 sp 0x7fff56eee6f0 T0)
#0 0x108d132a7 in btree<long>::find(long const&) const (test01+0x1000022a7)
AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV (test01+0x1000022a7) in btree<long>::find(long const&) const
==7345==ABORTING
Abort trap: 6
当我尝试在另一台机器上运行时，我也遇到了这个错误：
==29936==ERROR: AddressSanitizer failed to allocate 0x200000 (2097152) bytes of SizeClassAllocator32: 12
我发现当它进入find（）时，会出现分段错误：
/**
* Identical in functionality to the non-const version of find,
* save the fact that what's pointed to by the returned iterator
* is deemed as const and immutable.
*
* @param elem the client element we are trying to match.
* @return an iterator to the matching element, or whatever the
* const end() returns if no such match was ever found.
*/
template<typename T> typename btree<T>::const_iterator
btree<T>::find(const T& elem) const {
std::cout << "CONST ITERATOR'S FIND" << std::endl;
Node *tmp_ = root_;
std::cout << "1" << std::endl;
while(true) {
std::cout << "2" << std::endl;
size_t i;
std::cout << "3" << std::endl;
// go through all elements from root to tail
for (i = 0; i < tmp_->__occupied_size_; ++i) {
std::cout << "4" << std::endl;
if (tmp_->__elem_[i] == elem) {
std::cout << "5" << std::endl;
// find the elem, return an iterator
return const_iterator(tmp_, i, this);
std::cout << "6" << std::endl;
} else if (tmp_->__elem_[i] > elem) {
std::cout << "7" << std::endl;
// elem is not in current Node, go to descendants
// for the elem.
if (tmp_->__descendants_ == nullptr) {
std::cout << "8" << std::endl;
return cend();
std::cout << "9" << std::endl;
} else {
std::cout << "10" << std::endl;
tmp_ = tmp_->__descendants_[i];
std::cout << "11" << std::endl;
break;
}
}
}
// handling boundaries cases
if (i == tmp_->__occupied_size_) {
std::cout << "12" << std::endl;
if (tmp_->__descendants_[i] == nullptr) {
std::cout << "13" << std::endl;
return cend();
std::cout << "14" << std::endl;
} else {
std::cout << "15" << std::endl;
tmp_ = tmp_->__descendants_[i];
}
}
}
}
此查找的打印语句为：
CONST ITERATOR'S FIND
1
2
3
4
4
7
10
11
2
3
4
7
10
11
ASAN:DEADLYSIGNAL
答案 0 :(得分：1)
好的，基于此find函数的实现，我认为问题可能位于
if (tmp_->__descendants_ == nullptr) {
std::cout << "8" << std::endl;
return cend();
std::cout << "9" << std::endl;
} else {
std::cout << "10" << std::endl;
tmp_ = tmp_->__descendants_[i];
std::cout << "11" << std::endl;
break;
}
然后
// handling boundaries cases
if (i == tmp_->__occupied_size_) {
std::cout << "12" << std::endl;
if (tmp_->__descendants_[i] == nullptr) {
std::cout << "13" << std::endl;
return cend();
std::cout << "14" << std::endl;
} else {
std::cout << "15" << std::endl;
tmp_ = tmp_->__descendants_[i];
}
}
因此，您正在检查tmp-＆gt; __ descendants_是否为空。如果不是，则设置tmp_ = tmp _-＆gt; descendants_ [i];
注意：您只是检查__descendants_指针是否为null，如果它为null，则不检查__descendants_ [i]！
如果tmp-> __ descendants_ [i]为空（或从后代数组中删除）怎么办？
如果该值为null，则tmp _-＆gt; occupied_size_可能会为您提供段错误。
注意2：出于某种原因，您使用相同的索引“i”来迭代__elem_和__descendants_。我不确定，后代是如何创建的，但这也可能是一个问题。
答案 1 :(得分：1)
这就是调试器存在的原因。在调试器中运行程序，让程序失败，然后调试器会告诉你它出错的地方和原因。
看起来你可能有很多代码需要搜索，这里没有人会真正想做，因为它不是一个简洁的问题。
祝你好运！