My task was to make a C# program to print information about entered permutations, including

• order
• parity
• signature
• decomposition into disjoint cycles

It originally had a full-featured GUI (Windows Forms), which I decided to strip off. This repository is a VS solution, consisting of 2 projects, one of which contains unit tests.

Permutations.Permutation and Permutations.Cycle represent permutations and permutations cycles, respectively. They both have from_string methods that can be used to construct an instance of the respective class from a string representation of a permutation or a cycle.

Note: the product ab represents the permutation a(b(∙))

String representation formats:

Cycles

Any number of positive integers separated by whitespace characters. Each cycle must be enclosed with parentheses e.g.

(1 2 3)

Permutations

A sequence of cycles, optionally followed by ^ <power>. If ^ <power> is present, cycles must be wrapped with square brackets.

  (1 2 3)(4 5 6) // valid
  (1 2 3)(4 5 6) ^ 7 // not valid
  [(1 2 3)(4 5 6)] ^ 7 // valid

Command line interface

Displays properties of entered permutations. If the input is empty, it will a generate a random permutation. Example:

Wolfram Alpha results for permutations above: 1, 2, 3.