thumb rule for using auto&& and const auto & : I have studied auto and I know it deduces types from initialized values. So if I try to write certain thumb rule for usage of auto, can I put below statements as rule-  

1) Use auto && for all values   (r-values and l-value, as It is universal ref)those are modifiable.  
2)const auto & - for read only values.  
3) Use auto wherever possible  (individual preference for coding style)  


