1字节=8位
无符号8位的取值范围= 2^8
1k=1024字节=2^10
1m=1024k
1g=1024m
| C语言 | 16位编辑器 | 32位编辑器 | 64位编辑器 | |||
|---|---|---|---|---|---|---|
| 数据类型 | 占用字节 | 取值范围 | 占用字节 | 取值范围 | 占用字节 | 取值范围 |
| char | 1 | -128~127 | 1 | -128~127 | 1 | -128~127 |
| unsigned char | 1 | 0～256 | 1 | 0～256 | 1 | 0～256 |
| short int | 2 | -32768～32767 | 2 | -32768～32767 | 2 | -32768～32767 |
| int | 2 | -32768～32767 | 4 | -2147483648～2147483647 | 4 | -2147483648～2147483647 |
| unsigned int | 2 | 0～65536 | 4 | 0～4294967296 | 4 | 0～4294967296 |
| float | 4 | 1.4013E-45~3.4028E+38 | 4 | 1.4013E-45~3.4028E+38 | 4 | 1.4013E-45~3.4028E+38 |
| double | 8 | 4.9E-324~1.7977E+308 | 8 | 4.9E-324~1.7977E+308 | 8 | 4.9E-324~1.7977E+308 |
| long | 4 | -2147483648～2147483647 | 4 | -2147483648～2147483647 | 8 | -2^63 ~ 2^63-1 |
| long long | 8 | -2^63 ~ 2^63-1 | 8 | -2^63 ~ 2^63-1 | 8 | -2^63 ~ 2^63-1 |
| unsigned long | 4 | 0 ~ 2^32 | 4 | 0 ~ 2^32 | 8 | 0~2^64 |
| java | |||
|---|---|---|---|
| 数据类型 | 占用字节 | 取值范围 | 默认值 |
| boolean | 1 | true/false | false |
| byte | 1 | -128~127 | 0 |
| short | 2 | -32768~32767 | 0 |
| int | 4 | -2147483648～2147483647 | 0 |
| long | 8 | -2^63 ~ 2^63-1 | 0 |
| char | 2 | -32768~32767 | \u0000 （Unicode表示空格） |
| float | 4 | 1.4013E-45~3.4028E+38 | 0.0f |
| double | 8 | 4.9E-324~1.7977E+308 | 0.0d |