如何定义在运行时成员数组的大小 [英] How to define member array size at runtime

问题描述

让我们说我有，有一个成员是一个数组类。是否有可能定义构造时其尺寸/在运行时，以下列方式：

Let's say I have a class that has a member which is an array. Is it possible to define its size upon construction/at run-time, in the following way:

class myClass {
    private:
        int myArray[n]
    public:
        myClass();
        someOtherMethod();
};

其中n是基于用户输入定义的变量。如果不是这样，这将是最好的选择？

Where n is a variable that is defined based on user input. If not, what would be the best alternative?

推荐答案

使用向量。

class myClass {
    private:
        std::vector<int> myArray;
    public:
        myClass();
        someOtherMethod();
};

myClass::myClass (int size)
    : myArray (size)
{ 
    ...
}

然后，您可以在矢量，你会数组填补。或者，纳瓦兹指出，使用储备（），它保留空间新的元素，和/或的push_back（），这增加了元件到背面，一次一个。

Then, you can fill in the vector as you would an array. Alternatively, as Nawaz points out, use reserve(), which reserves space for new elements, and/or push_back(), which adds elements onto the back, one at a time.

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