exercism/csharp/secure-munchester-united

Secure Munchester United

Welcome to Secure Munchester United on Exercism's C# Track. If you need help running the tests or submitting your code, check out HELP.md. If you get stuck on the exercise, check out HINTS.md, but try and solve it without using those first :)

Introduction

Casting and type conversion are different ways of changing an expression from one data type to another.

An expression can be cast to another type with the cast operator (<type>).

long l = 1000L;
int i = (int)l;

object o = new Random();
Random r = (Random)o;

If the types are not compatible an instance of InvalidCastException is thrown. In the case of numbers this indicates that the receiving type cannot represent the cast value. In the case of classes, one of the types must be derived from the other (this also applies trivially to structs).

An alternative to casting is type conversion using the is operator. This is typically applied to reference and nullable types.

object o = new Random();
if (o is Random rand)
{
    int ii = rand.Next();
    // now, do something random
}

If you need to detect the precise type of an object then is may be a little too permissive as it will return true for a class and any of the classes and interfaces from which it is derived directly or indirectly. typeof and Object.GetType() are the solution in this case.

object o = new List<int>();

o is ICollection<int> // true
o.GetType() == typeof(ICollection<int>) // false
o is List<int> // true
o.GetType() == typeof(List<int>) // true

Instructions

Our football club exercise:csharp/football-match-reports is soaring in the leagues, and you have been invited to do some more work, this time on the security pass printing system.

The class hierarchy of the backroom staff is as follows

TeamSupport (interface)
├ Chairman
├ Manager
└ Staff (abstract)
    ├ Physio
    ├ OffensiveCoach
    ├ GoalKeepingCoach
    └ Security
        ├ SecurityJunior
        ├ SecurityIntern
        └ PoliceLiaison

A complete implementation of the hierarchy is provided as part of the source code for the exercise.

All data passed to the security pass maker has been validated and is guaranteed to be non-null.

1. Get display name for a member of the support team as long as they are staff members

Please implement the SecurityPassMaker.GetDisplayName() method. It should return the value of the Title field instances of all classes derived from Staff and, otherwise, "Too Important for a Security Pass".

var spm = new SecurityPassMaker();
spm.GetDisplayName(new Manager());
// => "Too Important for a Security Pass"
spm.GetDisplayName(new Physio());
// => "The Physio"

2. Customize the display name for the security team

Please modify the SecurityPassMaker.GetDisplayName() method. It should behave as in Task 1 except that if the staff member is a member of the security team (either of type Security or one of its derivatives) then the text " Priority Personnel" should be displayed after the title.

var spm = new SecurityPassMaker();
spm.GetDisplayName(new Physio());
// => "The Physio"
var spm2 = new SecurityPassMaker();
spm2.GetDisplayName(new Security());
// => "Security Team Member Priority Personnel"
spm2.GetDisplayName(new SecurityJunior());
// => "Security Junior Priority Personnel"

3. Only designate principal security team members as priority personnel

Please modify the SecurityPassMaker.GetDisplayName() method. It should behave as in Task 2 except that the text " Priority Personnel" should not be displayed for instances of type SecurityJunior, SecurityIntern and PoliceLiaison.

var spm2 = new SecurityPassMaker();
spm2.GetDisplayName(new Security());
// => "Security Team Member Priority Personnel"
spm2.GetDisplayName(new SecurityJunior());
// => "Security Junior"

Source

Created by

• @mikedamay

Contributed to by

• @ErikSchierboom
• @yzAlvin