Data type can be defined as a type of data that we use in our programs. Each variable that we use in programs must have a data type. In C++, there is 3 types of data types:-
- In built data types.
- User defined data types.
- Derived data types
- In built data types:- These are the predefined data types which has special meaning to the compiler.
eg: int, char, float etc.
Data Types Size (in bytes) Range Char 1 -128 to 127 Integer 2 -32768 to 32767 Float 4 3.4*10-38 to 3.4*1038 Double 8 1.7*10-308 to 1.7*10308
Integer can be further classified into following:
- Short (-32768 to 32767)
- Long (-2,147,483,648 to 2,147, 483,647)
- Unsigned (up to 65536)
Floating point Data type can be categorized as:
- Float (3.4E +/- 38 (7 digits))
- Double (1.7E +/- 308 (15 digits))
- Long Double (1.7E +/- 308 (15 digits))
- Derived data types:- These data types are derived from the in built data types. .
eg: Array, Function, Pointer, reference.
- Array:- Array is derived data type used to store data of similar data type. All elements in array stored in contigous memory location.
- Function:- A function is a block of code that performs a specific task. Every function has a function name and it is reusable . it can be executed from as many different parts in Program as required, it can also return a value to calling program. All executable code resides within a function.
- Pointer:- Pointer is a variable use to store the address of another variable. With the help of pointer we can allocate or de allocate memory to variables.
- Reference:- Reference is the alternate name or another name to variables. We can use both the names of variable in our program.
eg: int mark;
eg: Structure, Union, Class, Enumeration.
- Structure:- In some programming contexts, you need to access multiple data types under asingle name for easy manipulation; for example you want to refer to address with multiple data like house number, street, zip code, country C supports structure which allows you to wrap one or more variables with different data types. A structure can contain any valid data types like int, char, float even arrays and other structures. Each variable in structure is called a structure member.
- Union:- Union is same as like structure except the allocation of memory for its members.Union occupies lower memory space as comapred to structure.
- Enumeration:-Enumeration is a set of constant and each constant has a name. We use enum keyword to create enum.