C language basics - basic data types and keywords

"The data type determines the size of the data storage space, expression method, data value range and operation method." 

Table of contents

Basic data types

        Integer data

        real data

        Character data

        string data

---

Basic data types

        Integer data

In C language, integer data is divided into three categories: basic integer (int), short integer (short) and long integer (long).

Integer data classification

type	type identifier	byte	Ranges
Signed basic shaping	[signed] int	4	-2147483648~2147483647
unsigned basic shaping	unsigned int	4	0~4294967295
signed short	[signed] short	2	-32768~32767
unsigned short	unsigned short	2	0~65535
signed long integer	[signed] long	4	-2147483648~2147483647
unsigned long integer	unsigned long	4	0~4294967295

        Note: "[]" in the table is an optional part, and the content in "[]" can be omitted when writing.

        real data

        Real data is also called floating point data. In C language, execution data is divided into three types: single precision type (float), double precision type (double) and long double precision type (long double). All real data are signed data and there is no unsigned data.

Classification of real data

type	type identifier	byte	Numeric range	decimal precision
Single precision type	float	4	~	7 bits
Double type	double	8	~	15 people
long double	long double	8	~	19th place

        Character data

        Character data is divided into character type (char) and unsigned character type (unsigned char).

Classification of character data

type	type identifier	byte	Ranges
Character type	char	1	-128~127
unsigned char type	unsigned char	1	0~255

        string data

        In the C language, there is no such type of string data. Generally speaking, we use character arrays (char []) to represent string data.