C ++ global pointer variable and member pointer variable Initialization

In C ++

The Member is a pointer variable, so it is best to initialize the pointer in the constructor. If it is not initialized, the compiler does not point this pointer to null. Therefore, when you use if (! Point)

Errors may occur during judgment, and debugging is troublesome.

But when you define a global pointer, if it is not initialized, the compiler will point this pointer to null.

However, the default value is not recommended. Not readable. It is also misleading. People subconsciously think that the compiler will point all the default values to null.