C# Variable

What is Variable

Computer memory location has an address and holds a content. The address is a numerical number (often expressed in hexadecimal), which is hard for programmers to use directly. Typically, each address location holds 8-bit (i.e., 1-byte) of data. It is entirely up to the programmer to interpret the meaning of the data, such as integer, real number, characters or strings.

A variable is a name of memory location. It is used to store data of a particular type. Its value can be changed and it can be reused many times.

Instead of numerical addresses, names (or identifiers) are attached to certain addresses.

It is a way to represent memory location through symbol so that it can be easily identified.

The following diagram illustrate the relationship between computers’ memory address and content; and variable’s name, type and value used by the programmers. The following diagram illustrate the relationship between computers’ memory address and content; and variable’s name, type and value used by the programmers.

Dynamic Memory Allocation are the most powerful features in C/C++ language, which allows programmers to directly manipulate memory to efficiently manage the memory – the most critical and scarce resource in computer – for best performance.

Basic Variable Type in C#

How to declare a variable

Let’s see the syntax to declare a variable:

variable_type variable_list;     

The example of declaring variable is given below:

int i, j;
double d;
float f;
char ch;

Here, i, j, d, f, ch are variables and int, double, float, char are data types.

We can also provide values while declaring the variables as given below:

int i=2,j=4;  //declaring 2 variable of integer type

float f=40.2;      

char ch=’B’;      

 Rules for defining variables

A variable can have alphabets, digits and underscore.

A variable name can start with alphabet and underscore only. It can’t start with digit.

No white space is allowed within variable name.

A variable name must not be any reserved word or keyword e.g. char, float etc.

Valid variable names:

int x;

int _x;

int k20;

Invalid variable names:

int 4;

int x y;

int double;