c++自定义类的无序集-插入时的段错误

Question

我正在遵循一个关于为游戏创建六边形地图的教程。源有它的结构，但我希望它是一个类，到目前为止，我无法使它工作。它编译得很好，但是当我试图插入一个新值时，它会出现分段错误。我可能做错了哈希函数，或者别的什么，但是我已经没有办法修复它了。谢谢!

c

#include <unordered_set>
#include "hexagonField.hpp"
int main(int argc, char **argv)
{
std::unordered_set <HexagonField> map;
map.insert(HexagonField(0, 0, 0));

return 0;
}

hexagonField.hpp

#ifndef HEXAGON_H
#define HEXAGON_H
#include <assert.h>
#include <vector>
class HexagonField
{
public:
const int q, r, s;
HexagonField(int q, int r, int s);
~HexagonField();
HexagonField hexagonAdd(HexagonField a, HexagonField b);
HexagonField hexagonSubtract(HexagonField a, HexagonField b);
HexagonField hexagonMultiply(HexagonField a, int k);
int hexagonLength(HexagonField hex);
int hexagonDistance(HexagonField a, HexagonField b);
HexagonField hexagonDirection(int direction /* 0 to 5 */);
HexagonField hexagonNeighbor(HexagonField hex, int direction);
const std::vector<HexagonField> hexagonDirections = {
HexagonField(1, 0, -1), HexagonField(1, -1, 0), HexagonField(0, -1, 1),
HexagonField(-1, 0, 1), HexagonField(-1, 1, 0), HexagonField(0, 1, -1)
};
bool operator == (const HexagonField comparedHex) const
{
return this->q == comparedHex.q && this->r == comparedHex.r && this->s == comparedHex.s;
}
bool operator != (const HexagonField comparedHex) const
{
return !(*this == comparedHex);
};
};
namespace std
{
template<>
struct hash<HexagonField>
{
size_t operator()(const HexagonField & obj) const
{
return hash<int>()(obj.q);
}
};
}
#endif

hexagonField.cpp

#include "hexagonField.hpp"
HexagonField::HexagonField(int q, int r, int s): q(q), r(r), s(s)
{
assert (q + r + s == 0);
}
HexagonField HexagonField::hexagonAdd(HexagonField a, HexagonField b)
{
return HexagonField(a.q + b.q, a.r + b.r, a.s + b.s);
}
HexagonField HexagonField::hexagonSubtract(HexagonField a, HexagonField b)
{
return HexagonField(a.q - b.q, a.r - b.r, a.s - b.s);
}
HexagonField HexagonField::hexagonMultiply(HexagonField a, int k)
{
return HexagonField(a.q * k, a.r * k, a.s * k);
}
int HexagonField::hexagonLength(HexagonField hex) {
return int((abs(hex.q) + abs(hex.r) + abs(hex.s)) / 2);
}
int HexagonField::hexagonDistance(HexagonField a, HexagonField b) {
return hexagonLength( hexagonSubtract(a, b));
}
HexagonField HexagonField::hexagonDirection(int direction /* 0 to 5 */) {
assert (0 <= direction && direction < 6);
return hexagonDirections[direction];
}
HexagonField HexagonField::hexagonNeighbor(HexagonField hex, int direction) {
return hexagonAdd(hex, hexagonDirection(direction));
}

Answer 1

如果您在调试器下运行您的程序，您将看到它在试图构造HexagonField对象时实际上溢出了堆栈。这是因为每个对象都有一个包含6个以上hexonfield对象的向量，而这些对象又需要另一个向量，以此类推。

作为快速修复，您可以将hexagonDirections从HexagonField类中取出，并将其移到hexonfield .cpp顶部的静态文件作用域变量中:

static const std::vector<HexagonField> hexagonDirections = {
HexagonField(1, 0, -1), HexagonField(1, -1, 0), HexagonField(0, -1, 1),
HexagonField(-1, 0, 1), HexagonField(-1, 1, 0), HexagonField(0, 1, -1)
};

或者，您可以将hexagonDirections保留为静态类成员，并将定义移动到您的.cpp文件:

// HexagonField.h
class HexagonField {
...
static const std::vector<HexagonField> hexagonDirections;
...
};

// HexagonField.cpp
const std::vector<HexagonField> HexagonField::hexagonDirections = {
HexagonField(1, 0, -1), HexagonField(1, -1, 0), HexagonField(0, -1, 1),
HexagonField(-1, 0, 1), HexagonField(-1, 1, 0), HexagonField(0, 1, -1)
};