三种类型之下分别是：short、int、long、char、float、double 这六个关键字
再加上两个符号说明符signed和unsigned就基本表示了C语言的最常用的数据类型。
下面列出了在32位操作系统下，常见编译器下的数据类型大小及表示的数据范围：
| 类型名称 | 占字节数 | 其他叫法 | 表示的数据范围 |
| char | 1 | signed char | -128 ~ 127 |
| unsigned char | 1 | none | 0 ~ 255 |
| int | 4 | signed int | -2,147,483,648 ~ 2,147,483,647 |
| unsigned int | 4 | unsigned | 0 ~ 4,294,967,295 |
| short | 2 | short int | -32,768 ~ 32,767 |
| unsigned short | 2 | unsigned short int | 0 ~ 65,535 |
| long | 4 | long int | -2,147,483,648 ~ 2,147,483,647 |
| unsigned long | 4 | unsigned long | 0 ~ 4,294,967,295 |
| float | 4 | none | 3.4E +/- 38 (7 digits) |
| double | 8 | none | 1.7E +/- 308 (15 digits) |
| long double | 10 | none | 1.2E +/- 4932 (19 digits) |
| C语言中的32个关键字 | |||
| auto | double | int | struct |
| break | else | long | switch |
| case | enum | register | typedef |
| char | extern | return | union |
| const | float | short | unsigned |
| continue | for | signed | void |
| default | goto | sizeof | volatile |
| do | if | static | while |
原文：https://www.cnblogs.com/mirocle/p/12114896.html