N

A nanosecond is one-billionth of a second.

A native data type is one defined in the C++ language, as opposed to a user-defined data type (class).

The new operator is used to allocate memory for variables of the dynamic storage class; these are usually variables whose storage requirements aren't known until the program is executing.

The newline character is the C++ character used to indicate the end of a line of text.

Nondisplay character; see nonprinting character.

A nonmember function is one that is not a member of a particular class being discussed, although it may be a member function of another class.

A nonnumeric variable is a variable that is not used in calculations like adding, multiplying, or subtracting. Such variables might represent names, addresses, telephone numbers, Social Security numbers, bank account numbers, or driver's license numbers. Note that even a data item referred to as a number and composed entirely of the digits 0 through 9 may be a nonnumeric variable by this definition; the question is how the item is used. No one adds, multiplies, or subtracts driver's license numbers, for example; these numbers serve solely as identifiers and could just as easily have letters in them, as indeed some of them do.

A nonprinting character is used to control the format of our displayed or printed information, rather than to represent a particular letter, digit, or other special character. The space is one of the more important nonprinting characters.

A non-virtual function is one that is not declared with the virtual keyword either in the class in question or any base class of that class. This means that the compiler can decide at compile time the exact version of the function to be executed when it is referred to via a base class pointer or base class reference.

A normal constructor is a constructor whose arguments supply enough information to initialize all of the member fields in the object being created.

A null byte is a byte with the value 0, commonly used to indicate the end of a C string. Note that this is not the same as the character “0”, which is a normal printable character having the ASCII code 48.

A null object is an object of some (specified) class whose purpose is to indicate that a “real” object of that class does not exist. It is analogous to a null pointer. One common use for a null object is as a return value from a member function that is supposed to return an object with some specified properties but cannot find such an object. For example, a null StockItem object might be used to indicate that an item with a specified UPC cannot be found in the inventory of a store.

A null pointer is a pointer with the value 0. This value is particularly suited to indicate that a pointer isn't pointing to anything at the moment, because of some special treatment of zero-valued pointers built into the C++ language.

A null string is a string or C string with the value “”.

A numeric digit is one of the digits 0 through 9.

A numeric variable is a variable that represents a quantity that can be expressed as a number, whether a whole number (an integer variable) or a number with a fractional part (a floating-point variable), and that can be used in calculations such as addition, subtraction, multiplication, or division. The integer variable types in C++ are char, short, int, and long. Each of these can be further subdivided into signed and unsigned versions. The signed versions can represent both negative and positive values (and 0), whereas the unsigned versions can represent only positive values (and 0) but provide greater ranges of positive values than the corresponding signed versions do. The floating-point variable types are float and double, which differ in their range and precision. Unlike the integer variable types, the floating-point types are not divided into signed and unsigned versions; all floating-point variables can represent either positive or negative numbers as well as 0. See float and double for details on range and precision.