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When we declare a pointer variable like so, its content is not intialized:
int* ptr;
In other words, it contains an address of “somewhere”, which is of course not a valid location. This is dangerous! We need to initialize a pointer by assigning it a valid address.
But suppose we don’t know where we are pointing to, we can use a null pointer.
nullptr
is a new keyword introduced in C++11. It provides a typesafe pointer value representing an empty pointer.
We can use nullptr
like so:
int* ptr = nullptr;
Note: In older C/C++ code, NULL
was used for this purpose. nullptr
is meant as a modern replacement to NULL
.
Instructions
1.
Change the declaration of ptr
and initialize it to nullptr
.
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