Mirrors/cppbestpractices
1
0
Fork 0
mirror of https://github.com/cpp-best-practices/cppbestpractices.git synced 2025-12-17 11:14:35 +03:00
Code Issues Actions Packages Projects Releases Wiki Activity

Update comments on double vs float

Browse Source 
See also #46
This commit is contained in:
Jason Turner
2015-12-30 13:30:38 -07:00
parent 571b39ca31
commit 1c2491c384
1 changed files with 5 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

7
08-Considering_Performance.md
View File

@@ -265,10 +265,13 @@ for (int i = 0; i < 15; ++i)
// obj is still taking up memory for no reason
```
### Prefer `double` to `float`
### Prefer `double` to `float`, But Test First
Operations on `double`s are typically faster than `float`s. However, in vectorized operations, `float` might win out. Analyze the code and find out which is faster for your application!
Depending on the situation and the compiler's ability to optimize, one may be faster over the other. Choosing `float` will result in lower precision and may be slower due to conversions. On vectorizable operations `float` may be faster if you are able to sacrifice precision.
`double` is the recomended default choice as it is the default type for floating point values in C++.
See this [stackoverflow](http://stackoverflow.com/questions/4584637/double-or-float-which-is-faster) discussion for some more information.
### Prefer `++i` to `i++`
... when it is semantically correct. Pre-increment is [faster](http://blog2.emptycrate.com/content/why-i-faster-i-c) than post-increment because it does not require a copy of the object to be made.