C++ 中的 double 与 double*

Question

I'm developing a piece of code which makes scientific calculation, and as a result I use extensive use of double variables. These variables travel from function to function, but most of them are never modified and hence defined as const in function signatures.

I have used double* in function signatures, but then I started to wonder that whether it's better to use double instead because:

• double* and double are same size, 8 bytes in C++.
• When I send in double* , I need another fetch operation in the function.

When using the variables in const fashion, are there any valid reasons to use double* instead of double ?

Answer 1

Here's the crust of the matter:

• First of all it's always a good idea to use pass-by-value for native data types (see here ) if you have no special requirements such as:
  • Transferring arrays via the variable
  • Keep inter-object relations (as outlined here )
  • And similar
• Transferring references have negligible performance affects for most cases.
• Be careful while using const , if you need to change the variable later, it's extra refactorization work, nevertheless const correctness is important .