Data types in C

Data types in C

Data types refer to an extensive system used for declaring variables or functions of different types before its use. The type of a variable determines how much space it occupies in storage and how the bit pattern stored is interpreted. The value of a variable can be changed any time. 

C has the following 4 types of data types

Basic built-in data types: int, float, double, char

Enumeration data type: enum

Derived data type: pointer, array, structure, union

Void data type: void

A variable declared to be of type int can be used to contain integral values only—that is, values that do not contain decimal places. A variable declared to be of type float can be used for storing floating- point numbers (values containing decimal places). The double type is the same as type float, only ith roughly twice the precision. The char data type can be used to store a single character, such as the letter a, the digit character 6, or a semicolon similarly A variable declared char can only store character type value. 

There are two types of type qualifier in c

Size qualifier: short, long

Sign qualifier: signed, unsigned

When the qualifier unsigned is used the number is always positive, and when signed is used number may be positive or negative. If the sign qualifier is not mentioned, then by default sign qualifier is assumed. The range of values for signed data types is less than that of unsigned data type. Because in signed type, the left most bit is used to represent sign, while in unsigned type this bit is also used to represent the value. The size and range of the different data types on a 16 bit machine is given below: