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C and C++ perform such promotion for objects of Boolean, character, wide character, enumeration, and short integer types which are promoted to int, and for objects of type float, which are promoted to double. Unlike some other type conversions, promotions never lose precision or modify the value stored in the object. In Java:
In computer programming, run-time type information or run-time type identification (RTTI) [1] is a feature of some programming languages (such as C++, [2] Object Pascal, and Ada [3]) that exposes information about an object's data type at runtime. Run-time type information may be available for all types or only to types that explicitly have it ...
Although static_cast conversions are checked at compile time to prevent obvious incompatibilities, no run-time type checking is performed that would prevent a cast between incompatible data types, such as pointers. A static_cast from a pointer to a class B to a pointer to a derived class D is ill-formed if B is an inaccessible or ambiguous base ...
Some features of C++ that promote more type-safe code: The new operator returns a pointer of type based on operand, whereas malloc returns a void pointer. C++ code can use virtual functions and templates to achieve polymorphism without void pointers. Safer casting operators, such as dynamic cast that performs run-time type checking.
The reinterpret cast technique from C/C++ also works in Pascal. This can be useful, when eg. reading dwords from a byte stream, and we want to treat them as float. Here is a working example, where we reinterpret-cast a dword to a float:
While we could also convert myObject to a compile-time String using the universal java.lang.Object.toString(), this would risk calling the default implementation of toString() where it was unhelpful or insecure, and exception handling could not prevent this. In C++, run-time type checking is implemented through dynamic_cast.
For the purposes of these tables, a, b, and c represent valid values (literals, values from variables, or return value), object names, or lvalues, as appropriate.R, S and T stand for any type(s), and K for a class type or enumerated type.
An object's virtual method table will contain the addresses of the object's dynamically bound methods. Method calls are performed by fetching the method's address from the object's virtual method table. The virtual method table is the same for all objects belonging to the same class, and is therefore typically shared between them.