What is variable in c ?

What is variable in c ?

• Variables are a way of reserving memory to hold some data.
• A variable is an identifier for a memory location in which data can be stored and subsequently recalled.
• Variables are used for holding data values so that they can be utilized in various computations in a program.
• Every variable is mapped to a unique memory address.
• Variables are used for holding data values so that they can be utilized in various computations in a program.

All variables have three important attributes.

• A data type that is established when the variable is defined, e.g., integer, real, character. Once 
• defined,the type of a C variable cannot be changed.
• A value that can be changed by assigning a new value to the variable. The kind of values a variable can assume depends on its type. For example, an integer variable can only take integer values, e.g., 2, 100, –12.
• The number of characters that you can have in a variable name will depend upon your compiler. A minimum of 31
• characters must be supported by a compiler that conforms to the C language standard.

RULES FOR NAMING C VARIABLE:

• Variable name must begin with letter or underscore.
• Variables are case sensitive
• They can be constructed with digits, letters.
• No special symbols are allowed other than underscore.
• sum, height, _value are some examples for variable name

TYPES OF VARIABLES IN C PROGRAM 

1. Local variable
2. Global variable
3. Environment variable