Question: I have a C++ interface with two methods. Any class implementing this interface need to implement at least one of the two methods but may define both. It is however not necessary to define both. What is the best pattern to use in such situation ?

Answer: 
```
```{r eval=FALSE}

```

The document will display the code by default but will prevent the code block from being executed, and thus will also not display any results.
For muting `library("name_of_library")` codes, meanly just showing the codes, `{r loadlib, echo=T, results='hide', message=F, warning=F}` is great. And imho a better way than `library(package, warn.conflicts=F, quietly=T)`