我可以使用已删除指针的名称吗？

Question

Is it allowed to use a pointer's name of a pointer once deleted?

This code, for instance, won't compile.

    int hundred = 100;
    int * const finger = &hundred;
    delete finger;

    int * finger = new int; // error: conflicting declaration 'int* finger'

This won't either:

    int hundred = 100;
    int * const finger = &hundred;
    delete finger;

    int finger = 50; // error: conflicting declaration 'int finger'

Answer 1

No. The int * is still an living object. The lifetime of the int that it pointed to has ended.

Note that

int hundred = 100;
int * const finger = &hundred;
delete finger;

has undefined behaviour, as you have attempted to delete an object that was not allocated by new .

In general, new and delete should not appear in C++ programs. Owning pointers should be std::unique_ptr (or rarely std::shared_ptr or other user-defined smart pointer type).