Implementing an interface C# with Example

An interface is used to enforce the presence of a method in any class that 'implements' it. The interface is defined 
with the keyword interface and a class can 'implement' it by adding : InterfaceName after the class name. A class 
can implement multiple interfaces by separating each interface with a comma. 
: InterfaceName, ISecondInterface 
public interface INoiseMaker 
{ 
string MakeNoise(); 
} 
public class Cat : INoiseMaker 
{ 
public string MakeNoise() 
{ 
return "Nyan"; 
} 
} 
public class Dog : INoiseMaker 
{ 
public string MakeNoise() 
{ 
return "Woof"; 
} 
} 
Because they implement INoiseMaker, both cat and dog are required to include the string MakeNoise() method 
and will fail to compile without it.