Collection of C++ snippets
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counted
=======
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```c++
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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:
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```c++
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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.
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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).