数组声明、大小定义和c++中的销毁

So I'm unsure as to what the correct way is to do this. I have a class named someClass, with a private variable that is an array of integers. The size doesn't get defined until the constructor is called. Here's how I do it:

所以我不确定正确的做法是什么。我有一个名为someClass的类，它的私有变量是一个整数数组。在调用构造函数之前，不会定义大小。我是这样做的:

In someClass.h:

在someClass.h:

class someClass {
public:
    someClass();
    someClass(int size);
    ~someClass();
private:
    int* array;
}

In someClass.cpp:

在someClass.cpp:

someClass::someClass() {
    array = new int[9];
}

someClass::someClass(int range) {
    array = new int[range];
}

someClass::~someClass() {
    delete[] array;
}

Did I declare/define the array correctly? Would it have been much better to use a vector?

我是否正确地声明/定义了数组?使用向量会更好吗?

Is the destructor correct?

析构函数是正确的?

2 个解决方案

#1

Yes, you're doing it correctly (partially), and yes, it would be better to use a std::vector (because of the "partially" part).

是的，您的操作是正确的(部分)，是的，最好使用std::vector(因为“部分”部分)。

The "partially" is that now you will have to provide a copy constructor and copy assignment operator for your class (and for efficiency, you might want to have a move constructor and move assignment operator as well); if you don't, you'll get double deletion errors if you ever copy the class.

“部分”是现在您必须为您的类提供一个复制构造函数和复制分配操作符(为了提高效率，您可能还需要一个移动构造函数和移动分配操作符);如果您不这样做，那么如果您复制类，您将会得到双重删除错误。

std::vector encapsulates all this, so this is why you should prefer it. Not to mention that it has nice features like iterators.

向量包含了所有这些，所以这就是为什么您应该更喜欢它。更不用说它有像迭代器这样的好特性。

Your class would then look like this:

你的班级会是这样的:

class someClass {
public:
    someClass();
    someClass(int size);
    //no destructor necessary!
private:
    std::vector<int> array;
}

someClass::someClass()
{} // nothing special needed

someClass::someClass(int range) : array(range)
{}

#2

You should also add copy ctor and copy assignment operator. Remember the rule of three!

您还应该添加copy ctor和copy赋值操作符。记住三原则!

#1