C++11: Casting

Overview

Lets say you have a Animal class and a Dog class. You make a pointer to Animal animal_ptr and you make it point to a Dog object.

Now you make a pointer to Dog and you make it point to animal_ptr. The compiler will complain. What should you do? You should cast it because you know that animal_ptr already points to a Dog object. You can find out more about casting here.

Content

C Style Cast

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Animal* animal_ptr = new Dog("Honey");
Dog* dog_ptr = (Dog)animal_ptr;

int i = 3;
Dog* dog2_ptr = (Dog)i; // will compile

Static Cast

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// Evaluated at compile time
Animal* animal_ptr = new Dog("Honey");
Dog* dog_ptr = static_cast<Dog>(animal_ptr);

Dynamic Cast

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// Evaluated at runtime, will return nullptr if it doesnt work
Animal* animal_ptr = new Dog("Honey");
Dog* dog_ptr = dynamic_cast<Dog>(animal_ptr);

Const Cast

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// removes const
const char* const_str = "Honey";
char* normal_str = const_cast<char*>(const_str);

Reinterpret Cast

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int anInt = 4;
// takes the bits from anInt and puts them into a double
double aDouble = reinterpret_cast<double>(anInt);