You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
43 lines
1.3 KiB
43 lines
1.3 KiB
13 years ago
|
counted
|
||
|
|
=======
|
||
|
|
|
||
|
13 years ago
|
```c++
|
||
|
13 years ago
|
for(auto x : counted(v)) {
|
||
|
|
... x.value ... x.index ...
|
||
|
|
}
|
||
|
|
```
|
||
|
|
`x.value` is a reference to the element in the container (so you can change it's value), `x.index` is what it is.
|
||
|
|
Container should have forward iterators.
|
||
|
|
|
||
|
|
|
||
|
|
This headers is purely a handy tool for the range-based-for-loops (ie `for(auto x : counter(v))`). Using it explicitly with iterators is not recommended!
|
||
|
|
|
||
|
|
|
||
|
|
There is no const version of it. Doing `for(const auto x : counted(v))` doesn't make it impossible to change `x` (so the element in the container can be modified).
|
||
|
|
|
||
|
|
|
||
|
|
Example:
|
||
|
13 years ago
|
|
||
|
|
```c++
|
||
|
13 years ago
|
for(auto x : counted(v)) {
|
||
|
|
std::cout << "v[" << x.index << "] = " << x.value << std::endl;
|
||
|
|
x.value *= 2;
|
||
|
|
}
|
||
|
|
```
|
||
|
|
This will output the container `v`, with it's indeces. And it will multiply every value in `v` by 2.
|
||
|
|
|
||
|
12 years ago
|
|
||
|
|
tuple element
|
||
|
|
=============
|
||
|
|
|
||
|
|
```c++
|
||
|
|
map<.., ..> m = {..};
|
||
|
|
for(auto key : keys(m))
|
||
|
|
... key ...
|
||
|
|
for(auto v : values(m))
|
||
|
|
... v ...
|
||
|
|
```
|
||
|
|
|
||
|
|
Some helper functions for easy access to maps. It also works well on vectors of tuples, or any container with a tuple-like interface.
|
||
|
|
The general function is `nth_values<N>(v)`, which allows you to iterate over the N-th element in the tuples of `v`.
|
||
|
|
For more information see tuple_element.h. Note that this does have a good const version, in contrast to the thing above (counted).
|