Crash in destructor

Hi,
Please let me know why it is crashing in destructor:

//Simulation of smart pointer

Code:

---

#include<iostream.h>

class smartpointer
{
public:
int *p;//ordinary pointer

public:
smartpointer(int n)
{
p =new int[n];
int *t =p;
for(int i=0;i<n;i++)
*t++=i*i;
}

int* operator++(int)
{
return p++;
}

int operator*()
{
return *p;
}

~smartpointer()
{
if(p)
delete [] p;
}

};

void main()
{
smartpointer sp(10);
for(int i=0;i<10;i++)
cout<<*sp++<<endl;
}

---

Ensure that p is initialized to 0.
The problem, it seems, is that your ++() returns p++, which is a temporary with the value of one past the address to which p refers. Thus *p++ is problematic, since the pointer p++ might not exist anymore.

so how can we delete the allocated memory in dTOR?

There are many problems with that class. Listing them from biggest to smallest problem:

1. Postincrement causes the class to delete a different pointer to the one that was returned from new.
2. It does not follow the rule of three.
3. It mixes the concept of smart pointer AND iterator. These should be separate concepts.
4. The constructor should probably be marked as explicit.
5. It unnecessarily check p for NULL before deletion.
6. It exposes the p member variable publicly, though this one is argueably acceptable.

Furthermore, the code is not indented. Indent!
Plus it uses void main. Use int main.