Episode 2 : Variable, Data Type

Data Type

When we write program, we use different kind of data. Such as, integer number, floating number, character etc.

We use mainly four kind of data types.

·        char : A single character can be defined as a character (char) type data. Character are usually stored in 8 bits ( 1 byte) of internal storage.

Example : char a; there ‘a’ is character type data. We can store a single character to use this and it take 1 byte from the memory.

·        int :  Whole integer number can be defined as a integer (int) type data. int takes 16 bit (2 byte) from the memory. C has three classes of integer there are, short int, int, long int. short int represents fairly small integer values and long int to increase the range of values.

Example : int a; there ‘a’ is a int type data and it hold integer value.

·        float : Floating number can be defined by the ‘float’ type. It takes 32 bit(4 byte) from the memory for holding floating data.

Example : float a; there ‘a’ is float type data and it takes 4 byte memory for storing float type data.

·        double : A double data type number (combine of int and float) uses 64 bits. ‘double’ type represents the same data type that float represents, but with a greater precision.

Example : double a; there ‘a’ is a double type data and it takes 8 byte memory for storing data.

The following  table represent the range of the data type :

Type	Minimum allowed range	Typical allowed range	Typical size in bytes
char	−127 → +127 or 0 → +255	−128 → +127 or 0 → +255	1
signed char	−127 → +127	−128 → +127	1
unsigned char	0 → +255	0 → +255	1
signed short int	−32767 → +32767	−32768 → +32767	2
unsigned short int	0 → +65535	0 → +65535	2
signed int	−32767 → +32767	−32768 → +32767 (antique systems) −2147483648 → +2147483647	2 or 4
unsigned int	0 → +65535	0 → +65535 (antique systems) 0 → +4294967295	2 or 4
signed long int	−2147483647 → +2147483647	−2147483648 → +2147483647 −9223372036854775808 → +9223372036854775807 (64-bit systems)	4 or 8
unsigned long int	0 → +4294967295	0 → +4294967295 0 → +18446744073709551615 (64-bit systems)	4 or 8
signed long long int	−9223372036854775807 → +9223372036854775807	−9223372036854775808 → +9223372036854775807	8
unsigned long long int	0 → +18446744073709551615	0 → +18446744073709551615	8
float	1×10−37 → 1×1037	1×10−37 → 1×1037	4
double	1×10−37 → 1×1037	1×10−308 → 1×10308	8
long double	1×10−37 → 1×1037	1×10−308 → 1×10308 1×10−4932 → 1×104932	8, 12, or 16

 

Written by "Shojib"