4 – C# Variable

C# Variable

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

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

The basic variable type available in C# can be categorized as:

Decimal, Boolean, Integral, Floating point, Nullable.

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
1 – A variable can have alphabets, digits and underscore.
2 – A variable name can start with alphabet and underscore only. It can’t start with digit.
3 – No white space is allowed within variable name.
4 – 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;