c++ - 如何从静态 vector 访问类元素？

Question

我有一个 class Town 的静态 vector 在同一个类中，我正在尝试访问它的元素。

代码:

// town.h
class Town
{
    public:
        static int nrOfTowns;
        static std::vector<Town> *towns;
        std::string name;
};

int Town::nrOfTowns = 0;
std::vector<Town> *Town::towns = NULL;

// main.cpp
/* code */
Town::towns = new std::vector<Town> (Town::nrOfTowns); // initializing vector
Town::towns[0].name; // gives me an error

我收到一个错误: class std::vector<Town>没有名为 name 的成员.

Answer 1

在您的代码中，towns 是一个指向 vector 的指针，但它可能应该是一个 vector :

// town.h
class Town
{
    public:
        static int nrOfTowns;
        static std::vector<Town> towns;
        std::string name;
};

int Town::nrOfTowns = 0;
std::vector<Town> Town::towns;

// main.cpp
/* code */
Town::towns.resize(Town::nrOfTowns);
Town::towns[0].name;

如果你真的想让它成为一个指针，你必须取消对指针的引用

// town.h
class Town
{
    public:
        static int nrOfTowns;
        static std::vector<Town> *towns;
        std::string name;
};

int Town::nrOfTowns = 0;
std::vector<Town> *Town::towns = nullptr;

// main.cpp
/* code */
Town::towns = new std::vector<Town> (Town::nrOfTowns); // initializing vector
(*Town::towns)[0].name; // gives me an error
delete Town::towns;