Khoá học lập trình C# (.NET Core) Bài tập ôn luyện OOP + Interface trong C# - Lập Trình C# - Lập Trình C Sharp

Question 1

I. Create an interface IPerson that has the following properties:

• string Skills — Read/Write

• DateTime DateOfBirth — Read-only

• int Age — Read-only

II. Create an abstract class named Employee that performs the following tasks:

1. Fields – private

• int _id — employee identity

• string _name — employee name

2. Constructor methods

• First constructor:
  Declare with one parameter int id, assign this value to the employee identity.
  The employee name is assigned a default value: "No name".

• Second constructor:
  Declare with two parameters int id, string name, then assign these values to the employee’s identity and name.

3. Properties – public

• int ID — Read-only property that returns the employee ID.

• string Name — Read/Write property of the employee name.

  • Must contain statements to throw a new Exception if the input name’s length is less than 3 characters.

4. Abstract method – public

• void ShowInfo() — without parameters.

III. Declaring class Programmer that inherits from abstract class Employee and implements interface IPerson.

1. Fields – private

• string _skills — programmer skills

• DateTime _DOB — date of birth

• int _age — age of programmer

2. Constructor methods

• First constructor with two parameters (int id, string name)
  → Call base constructor with (id, name) and assign default values:

  • _skills = string.Empty

  • _DOB = DateTime.Now

• Second constructor with three parameters (int id, string name, string skills, DateTime dob)
  → Call base constructor (id, name), then assign skills to _skills and dob to _DOB.

3. Properties – public

• string Skills — implement from IPerson, Read/Write.
  Must include statement to throw new Exception if input value’s length < 0.

• DateTime DateOfBirth — implement from IPerson, Read-only.
  Returns the value of _DOB.

• int Age — implement from IPerson, Read-only.
  Returns the real age of the programmer calculated from DateOfBirth.

4. Method – public

• void ShowInfo() — display all programmer information in the following format:

  Id: 1 | Name: Nguyen Van A | Skills: C#, SQL | DOB: 20/5/1990 | Age: 34
  

Question 2

I. Create a class named HiredProgrammers that performs the following tasks:

1. Field – private

• Declare a generic List<Programmer> named HPGM.

2. Constructor method

• Declare a constructor with one parameter int capacity to initialize the HPGM list with the given capacity.

3. Methods – public

• void AddNew(Programmer prog)
  Add a programmer object into the list HPGM.
  Must throw a new Exception when the list is out of capacity.

• int ShowFilterInfo(int underage)
  Display all information of programmers whose Age ≤ underage.
  Return the number of those programmers.

II. Create a class to test

1. Define an instance of HiredProgrammers class named myemployee, initialized with 3 as input capacity.

2. Write statements to input 3 programmers and add them into myemployee.
   Use try-catch blocks to handle exceptions during input.

3. In the console:

   • Input a value underage.

   • Invoke ShowFilterInfo(underage) with myemployee to display which programmers have an age less than or equal to that input value.

End of Question