Programming help :) part-1

Question

Hi Requirement : Create a program named SchoolsDemo that allows a user to enter data about five school objects and then displays the school objects in order of enrollment size from smalles to largest. The school class contains fields for the school name and number of students enrolled and properties for each field. Also include an Icompareable.CompareTo() method so that School Objects can be sorted by enrollment. What i have done : Starting issue itself unable to understand what question really expecting from me . But i am trying to find out Any ideas  Regards

Vulpes · Answer

Try this: using System; class School : IComparable { private string _name; private int _enrolment; public string Name { get { return _name; } set { _name = value; } } public int Enrolment { get { return _enrolment; } set { _enrolment = value; } } public School(string name int enrolment) { _name = name; _enrolment = enrolment; } public int CompareTo(object obj) { if (obj == null) return 1; School otherSchool = obj as School; if(otherSchool != null) return this._enrolment.CompareTo(otherSchool._enrolment); else throw new ArgumentException(Object is not a School); } } class SchoolsDemo { static void Main() { int numSchools = 5; School[] schools = new School[numSchools]; Console.WriteLine(Enter data for {0} schools
 numSchools); for(int i = 0; i { Console.Write( School #{0} -> Name :  i + 1); string name = Console.ReadLine(); Console.Write( School #{0} -> Enrolment :  i + 1); int enrolment = int.Parse(Console.ReadLine()); schools[i] = new School(name enrolment); Console.WriteLine(); } Array.Sort(schools); Console.WriteLine(
The schools sorted by enrolment are
); for(int i = 0; i { Console.WriteLine( Name : {0 -16} Enrolment : {1 4} schools[i].Name schools[i].Enrolment); } Console.ReadKey(); } }

Vulpes · Answer

If you don't use IComparable then you could sort the schools like this by writing your own 'bubble sort' routine. If you don't know what that is then check out this link: http://www.trinity.nottingham.sch.uk/computing/csharp/basics/bubbleSort.aspx using System; class School { private string _name; private int _enrolment; public string Name { get { return _name; } set { _name = value; } } public int Enrolment { get { return _enrolment; } set { _enrolment = value; } } public School(string name int enrolment) { _name = name; _enrolment = enrolment; } } class SchoolsDemo { static void Main() { int numSchools = 5; School[] schools = new School[numSchools]; Console.WriteLine(Enter data for {0} schools
 numSchools); for(int i = 0; i { Console.Write( School #{0} -> Name :  i + 1); string name = Console.ReadLine(); Console.Write( School #{0} -> Enrolment :  i + 1); int enrolment = int.Parse(Console.ReadLine()); schools[i] = new School(name enrolment); Console.WriteLine(); } SortSchools(schools); Console.WriteLine(
The schools sorted by enrolment are
); for(int i = 0; i { Console.WriteLine( Name : {0 -16} Enrolment : {1 4} schools[i].Name schools[i].Enrolment); } Console.ReadKey(); } static void SortSchools(School[] schools) { School temp = null; for (int i = schools.Length - 1; i > 0; i--) { for (int j = 0; j { if (schools[j].Enrolment > schools[j + 1].Enrolment) { temp = schools[j]; schools[j] = schools[j + 1]; schools[j + 1] = temp; } } } } }

Jay Patel · Answer

what if you don't have the last sentence of the question i.e icompareable thing how would the program look like then?

Vulpes · Answer

If a class or struct implements the IComparable inteface then this provides a mechanism whereby instances of the type in question can be compared to each other for ordering or sorting purposes. The interface has only one method CompareTo which takes an object parameter (another instance of the current type) and returns an int. If the return value is less than 0 then the current instance will precede the other instance in the sort order. If the return value is 0 then the current and other instances will have the same position in the sort order. If the return value is more than 0 then the current instance will follow the other instance in the sort order. Methods such as Array.Sort automatically (unless instructed to the contrary) use a type's CompareTo method to sort the elements of the array. So here after checking that the object is of the right type and is not null we make use of System.Int32's own CompareTo method to compare the _enrolment fields of the two instances. The array is then sorted in increasing order of _enrolment. It's more normal nowadays to use the generic version of IComparable which is strongly typed but as the question didn't specify this I've stuck to the non-generic version.

SUNIL GUTTA · Answer

Hi friend Once again Ty so much Well before me looking into code you given . I need some clarity on what the question really need .. I understand fields inside properties .. but what is the main theme of the question .. Please explain me so i can try my self and next look into the code given by you Regards