Things to Rember
1.Declaring something const helps compilers detect usage errors. const can be applied to objects at
any scope, to function parameters and return types, and to member functions as a whole.
2.Compilers enforce bitwise constness, but you should program using conceptual constness.
3.When const and non-const member functions have essentially identical implementations, code
duplication can be avoided by having the non-const version call the const version.
[EC++_item3]任何可能的时候都使用const,布布扣,bubuko.com
原文：http://www.cnblogs.com/pansj/p/EffectiveCPlusPlus_Item_3.html