mathematics

In this file I have written a c++ code to find the reverse of a string without using functions.

Description of Change

Checklist

What about create a design pattern directory with the most popular design patterns examples?
We can create some rules like: have to be an explanation about the design pattern, the structure and one real world example.
The directory can be:

(folder) Design Patterns
-- (folder) Abstract Factory
-- -- AbstractFactory.js
-- -- AbstractFactoryTest.js
-- -- REAME.md

I can send some :

Description of Change

References

Checklist

1. The rf204_extrangefit.py should be translated also to C++
2. The rf204b_extendedLikelihood_rangedFit.C tutorial should also be translated to C++
3. The [rf204b_extendedLikelihood_rangedFit.C](https://root.cern.ch/doc/master/rf204b__extendedLikelihood_

IEEE 754 recommends (but does not require) a compound function, which is in the process of being standardized for C and C++; we should expose it in swift-numerics. The simplest, most literal translation of the operation into Swift would be:

extension RealFunctions {
  /// (1+x)ⁿ
  /// 
  /// Returns NaN if x < -1.
  static func compound(_ x: Self, _ n: Int) -> Self {
    // not

This is a good starting point for new igraph contributors.

What is the feature or improvement you would like to see?

A graph generator for the generalized Petersen graph.

The construction for G(n,k) is as follows:

• Create a cycle graph on n vertices. Name these vertices as u_0, ..., u_(n-1).
• Create n more vertices, v_0, ..., v_(n-1) and connect each u_i to its c