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C++ variables

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Variables are simply names used to refer to some location in memory – a location that holds a value with which we are working. Size of variables depends upon data type used to define it.

Syntax :

 data-type variable-name ; 

Rules for defining variables in C++

  • The name of a variable can be composed of letters(a-z, A-Z), digits(0-9), and the underscore character(_).
  • It must begin with either a letter or an underscore.
  • Name is case-sensitive means Upper and lowercase letters are distinct.
  • Blank spaces can't be used in variable names.

Example :

int EmployeeId;
double Salary;

Assigning values to variables :

int EmployeeId = 10;
double Salary = 10000.78;

The above line declares a variable names EmployeeId and assigns it a value 10.
The same objective can be achieved in following way:

int EmployeeId;
EmployeeId = 10;

Understanding the above code :

int EmployeeId;
It defines a variable named EmployeeId and occupies a memory (2 bytes) in Computer Memory which can store an integer value.
EmployeeId = 10;
This is known as assignment statement. A value 10 is assigned to the variable EmployeeId. The left hand side of = operator (lvalue) must be a variable name while the rvalue can be another variable or some value.


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