Variables in C

A variable is nothing but a name given to a storage area that our programs can manipulate. Each variable in C has a specific type, which determines the size and layout of the variable's memory; the range of values that can be stored within that memory; and the set of operations that can be applied to the variable.

The name of a variable can be composed of letters, digits, and the underscore character. It must begin with either a letter or an underscore. Upper and lowercase letters are distinct because C is case-sensitive.

There are some rules to choosing a variable name

• A variable name can consist of Capital letters A-Z, lowercase letters a-z, digits 0-9, and the underscore character.
• The first character must be a letter or underscore.
• Blank spaces cannot be used in variable names.
• Special characters like #, $ are not allowed.
• C keywords cannot be used as variable names.
• Variable names are case sensitive.
• Values of the variables can be numeric or alphabetic.
• Variable type can be char, int, float, double, or void.

Based on the basic types explained in the previous chapter, there will be the following basic variable types −

Sr.No.	Type & Description
1	char Typically a single octet(one byte). It is an integer type.
2	int The most natural size of integer for the machine.
3	float A single-precision floating point value.
4	double A double-precision floating point value.
5	void Represents the absence of type.

Some examples are −

extern int d = 3, f = 5;    // declaration of d and f. 
int d = 3, f = 5;           // definition and initializing d and f. 
byte z = 22;                // definition and initializes z. 
char x = 'x';               // the variable x has the value 'x'.

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