Data Types :

A data type is a set of values together with a set of operations that can be
performed on those values. In the C programming language, the data type of an
object determines how much memory is allocated for it, how the stored bit pattern
is interpreted, and what operations are permitted on the data.

C provides several standard (built-in) data types, such as int, double,
and char. The int data type is used to represent integer values, while
double is used to represent real numbers. The char data type is used to
represent individual characters. Because computer memory is finite, these data
types represent only a limited subset of the mathematical integers and real
numbers, but they are sufficient for most programming applications.

C DATA TYPES - Size & Ranges:

char

Size: 8 bits
Range: −128 to +127

unsigned char

Size: 8 bits
Range: 0 to 255

short int

Size: 16 bits
Range: −32,768 to +32,767

int

Size: 32 bits
Range: −2,147,483,648 to +2,147,483,647

unsigned int

Size: 32 bits
Range: 0 to 4,294,967,295

long / long int

Size: 32 bits
Range: −2,147,483,648 to +2,147,483,647

unsigned long

Size: 32 bits
Range: 0 to 4,294,967,295

enum

Size: 16 bits
Range: −2,147,483,648 to +2,147,483,647

float

Size: 32 bits
Range: 3.4 × 10⁻³⁸ to 3.4 × 10³⁸

double

Size: 64 bits
Range: 1.7 × 10⁻³⁰⁸ to 1.7 × 10³⁰⁸

long double

Size: 80 bits
Range: 3.4 × 10⁻⁴⁹³² to 1.1 × 10⁴⁹³²