数据类型范围
| 数据类型 | 最小值 | 最大值 |
|---|---|---|
| int | -21474836478 | 2147483647 (2^31-1) |
| unsigned int | 0 | 4294967295 (2^32 - 1) |
| long | -2147483648 | 2147483647 (2^31 - 1) |
| unsigned long | 0 | 4294967295 (2^32-1) |
| long long | -9223372036854775808 | 9223372036854775807 (2^64-1) |
| unsigned long long | 0 | 18446744073709551615 (2^64-1) |
| __int64 | -9223372036854775808 | 9223372036854775807 (2^64-1) |
ps：
32位系统long和int一样
64位系统long和long long一样
