[cpplings] Add modern C++ (14/17/20) feature exercises #525
Description
Enhancement
This sub-issue will add exercises covering modern C++ features to help users learn the syntax and libraries introduced in C++14, C++17, and C++20.
The exercises will include:
- C++14: Generic lambdas, auto return type deduction, variable templates
- C++17: Structured bindings, std::optional, std::variant, if-with-initializer
- C++20: Concepts, ranges, designated initializers
Understanding these modern C++ features will help with writing more concise and maintainable code in the MiniOB project.
Parent issue: #508 (add more cpplings case)