User defined data types in c plus plus?

Answer 1

C++ provides the following fundamental types:

• A Boolean type (bool)
• Character types (char and wchar_t)
• Integer types (int, short, long and long long)
• Floating-point types (float, double and long double)
• A type, void, used to signify the absence of information.

Fundamental types correspond to the basic storage units of the machine. From the fundamental types we can construct other types using declarator operators:

• Pointer types (such as int*)
• Array types (such as char[])
• Reference types (such as double& and char&&)

The Boolean, character and integer types are collectively known as the integral types. The integral and floating-point types are collectively known as the arithmetic types.

The fundamental types, pointers, arrays and references are collectively known as the built-in types.

The integral types can be further modified using the signed or unsigned modifiers. Strictly speaking, both long and short are also type modifiers because a short implies a short int. This is simply an artefact from C Programming where int was implied in the absence of an explicit type.

Note that aliases (using x = type) and type definitions (typedef) are not types per se, they are simply alternative names for preexisting types. For instance, although wchar_t is a built-in type because it does not require a declaration, in reality it is just an alias for an implementation-defined integral type (typically unsigned short).

From these built-in types we can construct other types:

• Data structures and classes (such as std::vector and std::string)
• Enumeration types (enum and enum class)

Data structures, classes and enumeration types are collectively known as user-defined types.

In essence, any type that requires an explicit declaration is a user-defined type. This includes all C++ standard library types such as std::string because we cannot use a std::string object unless we include the header where the type is declared.

Answer 2

An user-defined type in C++ is any type that is not a primitive or predefined type, including those provided by the standard library. Typically, a user-defined type is a class or union, but you can also define types based upon primitive types in order to simplify your code. For instance, rather than constantly having to write unsigned long long for a 64-bit unsigned value, you could reduce this to an user-defined type, such as uint64, simply by definining the type:

typedef unsigned long long uint64;

Now you can use the user-defined type uint64 everywhere you would have previously used unsigned long long. You've not actually changed the behaviour of the type, you've simply reduced a more complex definition to a much simpler, shorter one.

Answer 3

Any data type that is defined by the programmer. That is, any data type that is not built-in, including user-defined classes and structures.

// int is a built-in type.

// UINT is a user-defined type for an unsigned integer.

typedef unsigned int UINT;

Answer 4

It makes the programming both simpler and more natural. For example, if you have a data type for "date" (assuming the language doesn't support this data type natively), you can pass a "date" as a single parameter to a function/method. Also, the function/method can return a date (note that in most languages, a function or equivalent can only return a single value).

Answer 5

user can create his own data type for handling data that does not fit in one of the existing data types

Answer 6

Any type that is not a primitive or is not a pre-defined type is a user-defined type.

typedef unsigned long long UINT64; // user-defined unsigned 64-bit type.

Answer 7

classes are user define data types and behave like built-in types of a programming language

Answer 8

User Define Data type is created by user requirement ,user code.Simply say those data type created by user thats called is user define datatype

Answer 9

Show me the data types and I do stand a chance of answering your question. You show me nothing so you get a nothing answer.