What is a dangling pointer?

What is a dangling pointer?
A dangling pointer arises when you use the address of an object after
its lifetime is over. This may occur in situations like returning
addresses of the automatic variables from a function or using the
address of the memory block after it is freed. The following
code snippet shows this:

class Sample
{
public:
       int *ptr;
       Sample(int i)
       {
         ptr = new int(i);
       }

       ~Sample()
       {
         delete ptr;
       }
       void PrintVal()
       {
         cout << "The value is " << *ptr;
       }
};

void SomeFunc(Sample x)
{
 cout << "Say i am in someFunc " << endl;
}

int main()
{
 Sample s1 = 10;
 SomeFunc(s1);
 s1.PrintVal();
}

In the above example when PrintVal() function is
called it is called by the pointer that has been freed by the
destructor in SomeFunc.