What is interface casting for in C#? -

i understand how writing interface works in c#, example described here: codeguru explanation

interface iintelligence    {       bool intelligent_behavior();    }     class human: iintelligence    {       public human()       {           //.............       }  /// interface method definition in class implements       public bool intelligent_behavior()       {          console.writeline("........");          return true       }    } 

i confused following process of interface casting:

human human = new human(); // human object casted interface type iintelligence humaniq = (iintelligence)human; humaniq.intelligent_behavior(); 

what sense of having class (human in case) implement interface, , casting instance human interface? question not how works, why done.

.net offers 2 types of interface implementations implicit implementation , explicit implementation.

when using implicit implementation , become part of type interface example if have iperson interface :

public interface iperson { string name{get;} } 

and implement follows :

public class person:iperson { public string name{get; ....} } 

you can access (implicitly):

aperson.name; 

but if implement (explicitly) :

public class person:iperson { string iperson.name{get; ....} // notice there's no need include access modifier. } 

then can accessed using iperson interface:

((iperson)aperson).name; 

update:

actually ,explicit interface implementation allow implement different interfaces members have same name.(as shown in this tutorial)