In C, wide characters are represented using wchar_t, which can represent character values beyond the range of ordinary char on many implementations. A wide character constant uses the L prefix, such as L'A'. The null wide character terminates wide-character strings. The EOF macro is an integer input-status indicator, not a wide-character string terminator.
Programming in C MCQ - Constants, Variables and Data Types
External variables are declared at file scope and have static storage duration. They can be accessed by functions where their declarations are visible. An external variable without an explicit initializer is initialized to zero. The extern keyword can declare a variable defined in another translation unit.
A variable has a value and, when it denotes an object, an associated storage location. Two pointer variables can store the same address when they refer to the same object. The address-of operator (&) obtains the address of an appropriate object, while the dereference operator (*) accesses an object through a pointer.
Calling free on a dynamically allocated object releases its storage. The pointer variable passed to free is not automatically assigned NULL. After the object is freed, using a pointer that refers to the released storage is invalid. Programmers commonly assign NULL to a pointer after freeing its allocation to avoid accidentally using a dangling pointer.
An enumeration defines a set of named integer constants using the enum keyword. By default, the first enumerator has value zero and each subsequent enumerator increases by one, unless an explicit value is assigned. Enumerations make programs more readable by giving meaningful names to related integer values.
