Data Type: Data Type specifies the type of data that can be stored in a variable and the number of bytes required to represent a type. Following are a few examples of data types used in C:
char: This is the most basic data type in C. It stores a single character and requires a single byte of memory in a majority of the compilers.
int: As the name suggests, an int variable is used to store an integer. This data type is used to store integer values.
float: Decimal numbers (numbers with floating point value) with single precision are stored in this data type.
double: It is used to store decimal numbers (numbers with floating point value) with double precision.
|Basic data types||Memory requirements|
|char||1 byte (8 bits)|
|int||4 bytes (32 bits)|
|float||4 bytes (32 bits)|
|double||8 bytes (64 bits) which means more significant figures and an exponent of large magnitude.|
int a = 40; // positive integer data type
float b = 5.8967; // float data type
char c = 'Z'; // char data type
long d = 41657; // long positive integer data type
- Associates a variable with a specific data type. Example: int a; associate the variable 'a' with 'int' which means 'a' can hold only integer type of data.
- All variables must be declared before they are used.
- Declarations are usually done at the beginning of the C program.
- The declaration consists of specifying the data type first, followed by 1 or more variable names.
The above example should thus be written like this
int a,b; (or) int a; int b;
Now, what happens when the above-mentioned declaration statement is executed?
1) The compiler is informed that 'a' and 'b' are variables which can hold only integer values
2) It also allocates 4 bytes of memory for both 'a' and `b'