If I use layout* member variable as a smart pointer e.g.
usinginstead ofCode:public: auto_ptr<Layout*> layout;
Would it automatically delete the previous value upon reassignment ??Code:public: Layout* layout;
e.g. first this->layout = l1 willbe used
and then this->layout = l2 will be used.
so when l2 has been assigned would l1 be removed from memory automatically If I use smart pointer overthere ??
remember l1 and l2 are not smart pointers they are normal Layout* Pointers.
More correctly, it would be: auto_ptr<Layout> layout;
However, I avoid using auto_ptrs for members since they have unusual copy semantics, which means that my own class would have unusual copy semantics (unless I simply disable copying altogether).
It would not even compile, since you cannot directly assign a raw pointer to an auto_ptr.so when l2 has been assigned would l1 be removed from memory automatically If I use smart pointer overthere ??
Look up a C++ Reference and learn How To Ask Questions The Smart WayOriginally Posted by Bjarne Stroustrup (2000-10-14)
So Can I extend auto_ptr Class and add a overload for = operator for assignment that accepts a Raw Pointer and either Reinterpret Casts or makes a temporary auto_ptr from that raw pointer and return that ??
Yes you can, no you should not, since auto_ptr is not designed to be a base class and does not have a virtual destructor.So Can I extend auto_ptr Class
That is entirely unnecessary. If l1 and l2 are pointers to a dynamically allocated object, and own their respective objects, then the simple solution is to create an auto_ptr out of each of them, and then assign auto_ptrs.add a overload for = operator for assignment that accepts a Raw Pointer and either Reinterpret Casts or makes a temporary auto_ptr from that raw pointer and return that ??
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Then whats the solution to automatically delete the previous value after setting a new value ??
What exactly are you trying to do?Then whats the solution to automatically delete the previous value after setting a new value ??
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a Layout* pointer will be provided through Constructor.
which will be used inthe App Class
How ever There is a scope of changing the Layout using setLayout(Layout*) methd.
So if somebody call's setLayout() the previous value of Layout* member variable (which is set by the constructor) will be overwritten by the new one provided by setLayout() but that previous one still stays in memory.
I want the previous one will be automatically deleted from memory when the new One will be assigned.
I think the reset method of auto_ptr is what you're asking for.
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But How can I invoke that automatically If I dont have a =operator overload ??
EDIT
However I can Invoke that from setValue() too.
But would that delete the previously assigned value from memory ??
Yes.But would that delete the previously assigned value from memory ??
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