Interface in C #

The interface in C # is defined as a syntactical contract that all Interface inheritance classes should follow. The interface defines the " What " section of the contract and the derived classes define the " How " section of the contract.

Interface defines attributes, methods and events, which are members of that Interface. The Interface contains only declarations of these members. Defining members is the responsibility of the derived class. It often helps provide a standard Structure that derived classes should follow.

The abstract classes to some extent usually serve the same purpose, however, they are mainly used when there are only a few methods declared by the base class and the derived class implements function.

Declaring Interface in C #

To declare the Interface in C # we use the interface keyword. It is similar to class declaration. By default, the Interface command is public. This is the Interface declaration example in C #:

 public interface GiaoDich { //các thành viên của interface void xemGiaoDich (); double laySoLuong (); } 

For example:

The following example will illustrate the Interface implementation above:

 using System . Collections . Generic ; using System . Linq ; using System . Text ; using System ; namespace GiaoDienUngDung { public interface QTM GiaoDich { //các thành viên của interface void xemGiaoDich (); double laySoLuong (); } public class GiaoDich : QTMGiaoDich { private string ma_giao_dich ; private string ngay_giao_dich ; private double so_luong ; //Lớp GiaoDich kế thừa từ QTMGiaoDich public GiaoDich () { ma_giao_dich = " " ; ngay_giao_dich = " " ; so_luong = 0.0 ; } public GiaoDich ( string c , string d , double a ) { ma_giao_dich = c ; ngay_giao_dich = d ; so_luong = a ; } public double laySoLuong () { return so_luong ; } public void xemGiaoDich () { Console . WriteLine ( "Giao dịch: {0}" , ma_giao_dich ); Console . WriteLine ( "Ngày giao dịch: {0}" , ngay_giao_dich ); Console . WriteLine ( "Số lượng: {0}" , laySoLuong ()); } } class Tester { static void Main ( string [] args ) { GiaoDich so 1 = new GiaoDich ( "001" , "08/06/2018" , 789000.00 ); GiaoDich so2 = new GiaoDich ( "002" , "09/06/2018" , 4519000.00 ); so1 . xemGiaoDich (); so2 . xemGiaoDich (); Console . ReadKey (); } } } 

Running the above code we get the following result:

 Transaction: 001 
 Transaction date: 08/06/2018 
 Quantity: 789000 
 Transaction: 002 
 Transaction date: 09/06/2018 
 Quantity: 4519000 
 

According to Tutorialspoint

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