速查表：
| 类型 | 类型 | 字节数 |
|---|---|---|
| char | -128 ~ +127 | (1 Byte) |
| short | -32767 ~ + 32768 | (2 Bytes) |
| unsigned short | 0 ~ 65536 | (2 Bytes) |
| int | -2147483648 ~ +2147483647 | (4 Bytes) |
| unsigned int | 0 ~ 4294967295 | (4 Bytes) |
| long == int | -2147483648 ~ +2147483647 | (4 Bytes) |
| long long | -9223372036854775808 ~ +9223372036854775807 | (8 Bytes) |
| double | 1.7 * 10^308 | (8 Bytes) |
| float | +/- 3.40282e+038 | 4Bytes |
| long double | +/- 1.79769e+308 | 12Byte |