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C C++ interview questions

!!! C C++ interview questions !!!

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.

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