A variable provides us with named storage that our programs can manipulate. Each variable in C++ has a specific type, which determines the size and layout of the variable's memory; the range of values that can be stored within that memory; and the set of operations that can be applied to the variable. A very simple example of a variable is −
int my_val = 5;
Here we have a variable my_val of type int(integer) and having the value 5. More generally variables are defined as −
Or if you also want to initialize them −
type variable_name = value;
The name of a variable can be composed of letters, digits, and the underscore character. It must begin with either a letter or an underscore. Upper and lowercase letters are distinct because C++ is case-sensitive. Following are the basic types available in C++ −
Stores either value true or false.
Typically a single octet (one byte). This is an integer type.
The most natural size of an integer for the machine.
A single-precision floating point value.
A double-precision floating point value.
Represents the absence of type.
C++ also allows us to create more complex variables like Enumeration, Pointer, Array, Reference, Data structures, and Classes.