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

Make note of "" vs ''

Browse Source
This commit is contained in:
Jason Turner
2015-06-28 19:58:58 -06:00
parent f0afb2d5d2
commit 33b3aa64d0
1 changed files with 13 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

13
08-Considering_Performance.md
View File

@@ -281,3 +281,16 @@ Even if many modern compilers will optimize these two loops to the same assembly
You should be also aware that the compiler will not be able optimize this only for integer types and not necessarily for all iterator or other user defined types. You should be also aware that the compiler will not be able optimize this only for integer types and not necessarily for all iterator or other user defined types.
The bottom line is that it is always easier and recommended to use the pre-increment operator if it is semantically identical to the post-increment operator. The bottom line is that it is always easier and recommended to use the pre-increment operator if it is semantically identical to the post-increment operator.
### Char is a char, string is a string
```cpp
// Bad Idea
std::cout << someThing() << "\n";
// Good Idea
std::cout << someThing() << '\n';
```
This is very minor, but a `"\n"` has to be parsed by the compiler as a `const char *` which has to do a range check for `\0` when writing it to the stream (or appending to a string). A '\n' is known to be a single character and avoids many CPU instructions.
If used inefficiently very many times it might have an impact on your performance, but more importantly thinking about these two usage cases gets you thinking more about what the compiler and runtime has to do to execute your code.