在 C++ 中初始化一个 class 变量地址为 NULL？

Question

Lets assume that i have a class as shown below:

  class CBase
  {
      public:
         CBase(void){};
         ~CBase(void){};
         Sigintgen m_oSignals;// This is another class variable which i have not defined here.
   };

The code begins as shown below:

       main()
       {
           CBasec *ptr = new CBasec();
           I would want the following to happen as shown below:
           &(ptr->m_oSignals) should be equal to NULL. Can anyone please suggest me how to get this?
            &(ptr->m_oSignals) = NULL; //This was tried but compilation errors.    
       }

Advanced thanks for the support.

Answer 1

You can't. An object always exists once declared.

Instead you could dynamically allocate the Sigintgen when needed, and have CBase store a pointer (which can start as nullptr ).

Or use std::optional .