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C++ - Static_cast and Dynamic_cast A static_cast and dynamic_cast both performs conversion between pointers to related classes. The difference between static_cast and dynamic_cast is that, static_cast performs a cast statically at compile time. It performs no run-time checks and hence no runtime overhead. For example, int a = 10; float n = static_cast<float>(a); //it behaves as 'a' was a float at compile time. Where, dynamic_cast performs a cast 'dynamically' at runtime. It is used for handling polymorphism. Dynamic_cast makes sure that the result of the type conversion is valid and complete object of the requested class. For example, class Base{ }; class Derived : public Base { }; Base b, *ptrb; Derived d, *ptrd; ptrb = dynamic_cast*<Base *>(&d); //Works fine ptrd = dynamic_Cast<<Derived *>(&b); //Fail In the above example, first dynamic_cast statement will work appropriately because casting is done from derived class to base class and second dynamic_cast statement will give compilation error because base class to derived class class conversion is not allowed with dynamic_cast unless the base class is polymorphic. A polymorphic type has at least one virtual function which is declared or inherited. For example, class Base{virtual void dummy()}; //polymorphic class Dynamic_cast have a significant runtime overhead. Prajakta Pandit 01-3-2017 11:54 PM

Both static_cast and dynamic_cast can perform conversions. Both static_cast and dynamic_cast can perform conversions between pointers to related classes. Only the difference between them is that the static_cast performs the conversion between pointers of the non-polymorphic related classes and dynamic_cast performs the conversion of the polymorphic related classes. Nitin Durugkar 08-8-2013 06:25 AM

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