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There are several loopholes to pure const-correctness in C and C++. They exist primarily for compatibility with existing code. The first, which applies only to C++, is the use of const_cast, which allows the programmer to strip the const qualifier, making any object modifiable. The necessity of stripping the qualifier arises when using existing ...
The first two of these, const and volatile, are also present in C++, and are the only type qualifiers in C++. Thus in C++ the term "cv-qualified type" (for const and volatile) is often used for "qualified type", while the terms "c-qualified type" and "v-qualified type" are used when only one of the qualifiers is relevant.
The word cast, on the other hand, refers to explicitly changing the interpretation of the bit pattern representing a value from one type to another. For example, 32 contiguous bits may be treated as an array of 32 Booleans, a 4-byte string, an unsigned 32-bit integer or an IEEE single precision floating point value.
C++ is also more strict in conversions to enums: ints cannot be implicitly converted to enums as in C. Also, enumeration constants (enum enumerators) are always of type int in C, whereas they are distinct types in C++ and may have a size different from that of int. [needs update] In C++ a const variable must be initialized; in C this is not ...
Even functions can be const in C++. The meaning here is that only a const function may be called for an object instantiated as const; a const function doesn't change any non-mutable data. C# has both a const and a readonly qualifier; its const is only for compile-time constants, while readonly can be used in constructors and other runtime ...
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:
A basic example is in the argv argument to the main function in C (and C++), which is given in the prototype as char **argv—this is because the variable argv itself is a pointer to an array of strings (an array of arrays), so *argv is a pointer to the 0th string (by convention the name of the program), and **argv is the 0th character of the ...
I don't know the answer to this question, but it seems like a useful thing to be in this article, if someone else knows. The C-style cast operator (type) is in the table, but what about the special C++ cast operators static_cast<type>(), dynamic_cast<type>(), reinterpret_cast<type>(), and const_cast<type>()? These are mentioned at the top of ...