Here we explore:

• how concepts helps to have some optimized implementation for a subset of possible type parameters.
• benefits of using existing concepts from the standard library.

• slides about C++20 concepts

In the file concepts.cpp, we provide two implementations of the function increment(). The commented one is optimized for iterators which fulfill the requirements of the concept RandomAccessIterator.

1. Uncomment and complete the concept RandomAccessIterator: check that the class IterT has operator +=.
2. Find an existing concept in the standard library, which can replace the previous user-defined concept.