C# Variables


What Is a Variable?

A variable is like a container in a C# program in which a data value can be stored inside the computer's memory. The stored value can be referenced using the variable's name.

Variable Naming Conventions

The programmer can choose any name for a variable as per C# naming conventions, such as;

  • Variable names contain letters, digits, and underscore.
  • It must begin with a letter, underscore, or @ character.
  • The C# keywords must be avoided.
  • It is good practice to choose meaningful names to make the code more comprehensible.
  • Variable names are case-sensitive, so variables named num, Num, and NUM are treated as three individual variables.
  • Traditionally, C# variable names are created in all lowercase characters.
  • Character values of the char data type must be enclosed in single quotes, but character strings of the string data type must be enclosed between double-quotes.
  • The decimal data type is preferred for the storage of monetary values.

Variable Declaration

To create a new variable in a program it must be declared, specifying the type of data it may contain and its chosen name. The following is a variable declaration syntax.

data-type variable-name;

Examples

The following number variable of int type is declared in the first line and then initialized in the next line.

int number;      // Declared number variable
number = 100 ;   // Initialized.

The following body variable of the float type is declared and initialized simultaneously.

float body = 98.6f ; // Declared and initialized.

Multiple Variable Declaration

Multiple variables of the same data type can be created in a single declaration as a comma-separated list.

data-type variable-name1 , variable-name2 , variable-name3;

Examples

The following multiple variables of the int type are created in a single declaration.

int a, b, c;
a = 100;
b = 200;
c = 300;