在C ++中定义对象而不调用其构造函数 [英] Defining an object without calling its constructor in C++

问题描述

在C ++中，我想将一个对象定义为此类的成员：

In C++, I want to define an object as a member of a class like this:

Object myObject;

但是这样做会尝试调用它的无参数构造函数，该构造函数不存在。但是，我需要在包含类完成一些初始化之后调用构造函数。

However doing this will try to call it's parameterless constructor, which doesn't exist. However I need the constructor to be called after the containing class has done some initialising. Something like this.

class Program
{
public:
   Object myObject; //Should not try to call the constructor or do any initializing
   Program()
   {
      ...

      //Now call the constructor
      myObject = Object(...);
   }

}

推荐答案

存储指向 Object 而不是实际的 Object

Store a pointer to an Object rather than an actual Object

因此：

class Program
{
public:
   Object* myObject; // Will not try to call the constructor or do any initializing
   Program()
   {
      //Do initialization
      myObject = new Object(...);  // Initialised now
   }

}

不要忘记在析构函数中删除。现代C ++可以为您提供帮助，因为您可以使用 auto_ptr shared_ptr而不是原始内存指针。

Don't forget to delete it in the destructor. Modern C++ helps you there, in that you could use an auto_ptr shared_ptr rather than a raw memory pointer.

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