| Size | Range | Precision |
|---|---|---|
| 4 bytes | ±1.18 x 10-38 to ±3.4 x 1038 | 6-9 significant digits, typically 7 |
| 8 bytes | ±2.23 x 10-308 to ±1.80 x 10308 | 15-18 significant digits, typically 16 |
| 80-bits (12 bytes) | ±3.65 x 10-4951 to ±1.18 x 104932 | 18-21 significant digits |
| 16 bytes | ±3.36 x 10-4932 to ±1.18 x 104932 | 33-36 significant digits |
C++ 学习笔记（2） —— float 和 double 的精度
原文：http://www.cnblogs.com/zzy528/p/5276493.html