Archive for category Versus (vs)

Difference between ‘Shadowing’ and ‘Overriding’ (Shadowing vs Overriding) – C#

Posted by Rajanihanth in .Net, C#, Tech Tips-.Net, Versus (vs) on July 29, 2012

This is a very quick Tech-Tips..! Actually Shadowing is VB.Net concept, in C# this concept called hiding! We will see this chapter later. 🙂

Shadowing : Creating an entirely new method with the same signature as one in a base class.

Overriding: Redefining an existing method on a base class.

  • Both are used when a derived class inherits from a base class
  • Both redefine one or more of the base class elements in the derived class

If you want to read more regarding this, just follow this MSDN topic.


class A
 {
 public int M1()
 {
 return 1;
 }

 public virtual int M2()
 {
 return 1;
 }
 }

class B : A
 {
 public new int M1()
 {
 return 2;
 }

 public override int M2()
 {
 return 2;
 }
 }

class Program
 {
 static void Main(string[] args)
 {
 B b = new B();
 A a = (A)b;

 Console.WriteLine(a.M1()); //Base Method
 Console.WriteLine(a.M2()); //Override Method
 Console.WriteLine(b.M1());
 Console.WriteLine(b.M2());
 Console.Read();
 }
 }

The output is : 1, 2, 2, 2

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Difference between ‘ref’ and ‘out’ parameters (ref vs out) – C#

Posted by Rajanihanth in .Net, Tech Tips-.Net, Versus (vs) on July 14, 2012

  • Both are treated differently @ runtime but same in the compile time, so can’t be overloaded.
  • Both are passed by references except ‘ref’ requires that the variable to be initialized before passed.

ref:

class Program
 {
 static void M1(out int i)
 {
 i = 1;
 i += 1;
 }

static void Main(string[] args)
 {
 int j; //Not assigned
 M1(out j);
 Console.Write(j);
 Console.Read();
 }
 }
}

The output is : 2

out:

class Program
 {
 static void M1(ref int i)
 {
 i = 1;
 i += 1;
 }

 static void Main(string[] args)
 {
 int j=0; //Assigned
 M1(ref j);
 Console.Write(j);
 Console.Read();
 }
}

The output is same: 2, but we have to assigned the variable before used otherwise we will get an error.

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