cpp06
In C++, there are several types of casting operators that serve different purposes. Here are the main types of casts:
Static Cast (static_cast):
Used for general-purpose casting that does not involve polymorphism. It can perform conversions between related types (e.g., numeric conversions, pointer conversions, etc.). Resolved at compile-time. Less safe than dynamic_cast as it doesn't perform runtime type checking. cpp Copy code double doubleNumber = 3.14; int intNumber = static_cast(doubleNumber);
Dynamic Cast (dynamic_cast):
Used for safe casting in the context of polymorphism. Used with pointers or references to polymorphic types (types with at least one virtual function). Performs runtime type checking, making it safer than static_cast. Returns nullptr (for pointers) or throws std::bad_cast (for references) if the cast is not possible. cpp Copy code Base* basePtr = new Derived(); Derived* derivedPtr = dynamic_cast<Derived*>(basePtr); if (derivedPtr) { // Successfully casted } else { // Cast failed } Const Cast (const_cast):
Used to add or remove the const qualifier from a pointer or reference. Allows modification of const objects or conversion of non-const to const. Use with caution; modifying a genuinely const object can lead to undefined behavior. cpp Copy code const int x = 42; int* nonConstPtr = const_cast<int*>(&x); *nonConstPtr = 10; // Okay, but may lead to undefined behavior Reinterpret Cast (reinterpret_cast):
Used for low-level and potentially unsafe type conversions. Performs a binary reinterpretation of the data, often used for pointer conversions. Should be used sparingly and only in situations where the behavior is well understood. cpp Copy code int intValue = 42; double* doublePtr = reinterpret_cast<double*>(&intValue);
Scalar Conversion:
In C++, scalar types refer to the fundamental data types that represent single values. Scalar types are atomic, meaning they cannot be subdivided further. The primary scalar types in C++ include:
Integer Types:
int: Integer type (usually 32 bits). short: Short integer type. long: Long integer type. long long: Long long integer type. signed and unsigned versions of the above. cpp Copy code int myInt = 42; unsigned long long bigUnsignedInt = 123456789012345; Floating-Point Types:
float: Single-precision floating-point type. double: Double-precision floating-point type. long double: Extended precision floating-point type. cpp Copy code float myFloat = 3.14f; double myDouble = 3.14; Character Types:
char: Character type. signed char: Signed character type. unsigned char: Unsigned character type. cpp Copy code char myChar = 'A'; Boolean Type:
bool: Boolean type, representing true or false. cpp Copy code bool isTrue = true; Enumeration Types:
Enumerations (enum) create a user-defined type consisting of named integral constants. cpp Copy code enum Color { RED, GREEN, BLUE }; Color myColor = RED; Scalar types are the building blocks for more complex data types and structures in C++. They are manipulated directly at the machine level and are typically more efficient than higher-level abstractions. It's important to note that scalar types are distinct from aggregate types like arrays, structures, and classes, which can hold multiple values or elements.
In the context of scalar types (e.g., int, float, char), implicit conversions occur when assigning one type to another. Explicit scalar conversions can be done using casting operators. cpp Copy code int intValue = 42; double doubleValue = static_cast(intValue);
-inff, +inff, and nanf are representations of special floating-point values in C++. These values are related to the IEEE 754 floating-point standard, which is widely used to represent real numbers in a binary system. Here's what each of these values means:
-inff and +inff:
These represent negative infinity and positive infinity, respectively. Infinity is a concept in mathematics that represents an unbounded quantity. In floating-point arithmetic, when a computation overflows, the result may be assigned the value of positive or negative infinity, depending on the direction of the overflow. cpp Copy code #include #include
int main() { float positiveInfinity = std::numeric_limits::infinity(); float negativeInfinity = -std::numeric_limits::infinity();
std::cout << "Positive Infinity: " << positiveInfinity << std::endl;
std::cout << "Negative Infinity: " << negativeInfinity << std::endl;
return 0;
} The output might be:
mathematica Copy code Positive Infinity: inf Negative Infinity: -inf nanf:
nanf stands for "Not a Number" and represents an undefined or unrepresentable value. It is typically the result of operations that involve undefined mathematical operations, such as dividing zero by zero or taking the square root of a negative number. cpp Copy code #include #include
int main() { float nanValue = std::numeric_limits::quiet_NaN();
std::cout << "NaN: " << nanValue << std::endl;
return 0;
} The output might be:
makefile Copy code NaN: nan Operations involving nanf generally result in nanf. It's important to handle cases involving nanf appropriately in your code to avoid unintended consequences.
These special floating-point values are essential for representing a wider range of mathematical concepts and handling exceptional cases in numerical computations. When working with floating-point numbers in C++, it's crucial to be aware of these special values and their potential impact on calculations.
-inf, +inf, and nan are representations of special floating-point values in C++. These values are associated with the IEEE 754 floating-point standard, which is commonly used to represent real numbers in a binary system. Here's an explanation of each:
-inf and +inf:
-inf represents negative infinity, and +inf represents positive infinity. Infinity is a concept in mathematics that denotes an unbounded quantity. In floating-point arithmetic, when a computation overflows, the result may be assigned the value of positive or negative infinity, depending on the direction of the overflow. cpp Copy code #include #include
int main() { double positiveInfinity = std::numeric_limits::infinity(); double negativeInfinity = -std::numeric_limits::infinity();
std::cout << "Positive Infinity: " << positiveInfinity << std::endl;
std::cout << "Negative Infinity: " << negativeInfinity << std::endl;
return 0;
} The output might be:
mathematica Copy code Positive Infinity: inf Negative Infinity: -inf nan:
nan stands for "Not a Number" and represents an undefined or unrepresentable value. It is often the result of operations that involve undefined mathematical operations, such as dividing zero by zero or taking the square root of a negative number. cpp Copy code #include #include
int main() { double nanValue = std::numeric_limits::quiet_NaN();
std::cout << "NaN: " << nanValue << std::endl;
return 0;
} The output might be:
makefile Copy code NaN: nan Operations involving nan generally result in nan. It's crucial to handle cases involving nan appropriately in your code to prevent unintended consequences.
These special floating-point values are essential for representing a broader range of mathematical concepts and handling exceptional cases in numerical computations. When working with floating-point numbers in C++, it's important to be aware of these special values and their potential impact on calculations.
============= Serialization:
Serialization involves converting data structures or objects into a format that can be easily stored, transmitted, or reconstructed. Serialization is often done using libraries or custom code to convert objects to streams of bytes. Serialization is not a casting operation per se but involves converting data into a different representation. cpp Copy code // Example using a serialization library (e.g., Boost.Serialization) #include <boost/archive/text_oarchive.hpp>
std::ostringstream oss; boost::archive::text_oarchive oa(oss); oa << myObject; // Serialize the object to a string stream Each type of casting serves a specific purpose, and the choice of which one to use depends on the context and requirements of your code. It's essential to use casting operators judiciously and be aware of their implications.
type casting: https://cplusplus.com/doc/oldtutorial/typecasting/
https://www.codeproject.com/Articles/824516/Concept-of-NaN-IND-INF-and-DEN
https://www.tutorialspoint.com/cplusplus/cpp_overloading.html
https://www.oreilly.com/library/view/understanding-and-using/9781449344535/ch01.html
###################################################### Dynamic casting https://www.youtube.com/watch?v=CiHfz6pTolQ ##################################################### Static Cast and Reinterpret casting https://www.youtube.com/watch?v=pWZS1MtxI-A