C#

public static int Add(object x,object y)
{
	int First;
	int Second;
	try
	{
		First = (int)x;
		Second = (int)y;
		return First + Second;
	}
	catch(Exception ex)
	{
		throw new Exception("Invalid values");
	}
	return 0;
}

Guffa wrote:

hat's not sending argument by reference, that's sending references as arguments.

class Program
{
    public static int Add(ref int x, ref int y)
    { 
        int result = x + y;
        Console.WriteLine("{0}", result);
        Console.ReadLine();
        return 10;
    }
    static void Main(string[] args)
    {
       int FirstNo = 10;
       int SecondNo = 20;
       int sum = Add(ref FirstNo ,ref  SecondNo);
       Console.WriteLine("{0}", sum);
       Console.ReadLine();
    }
}

kabutar wrote:

return 10;

kabutar wrote:

also one more doubt in your code u have used a,b and first number and second number .what is the purpose of those.

public static void Add(int x, int y , ref int result)
{
   result = x + y;
}

static void Main(string[] args)
{
   int x = 5;
   int y = 5;
   int result = 0;
   Add(x , y , ref result);
   Console.WriteLine("{0}", result);
   Console.ReadLine();
}

public static void Add(int firstValue , int secondValue , ref int firstValueAddedToSecondValue)
{
   firstValueAddedToSecondValue = firstValue + secondValue;
}

static void Main(string[] args)
{
   int x = 5;
   int y = 5;
   int result = 0;
   Add(x , y , ref result);
   Console.WriteLine("{0}", result);
   Console.ReadLine();
}

public static bool Add(int x, int y, ref int result)
{
   try
   {
      result = ReallyComplexCalculationDoneBy3rdPartyLib( x , y );
   }
   catch( Exception e )
   {
      //handle exception - this is for example only
      return false;
   }

   return true;
}

static void Main(string[] args)
{
   int x = 5;
   int y = 5;
   int result = 0;

   bool AddWorked = Add(x , y , ref result);

   if (AddWorked)
      Console.WriteLine("{0}", result);
   else
      Console.WriteLine("Addition failed - check log file..etc");

   Console.ReadLine();
}

Exelioindia wrote:

entry point for that dll.

kabutar wrote:

so how does this statement work:: Animal a1 = new Dog();

class Animal
{
	public virtual void ShowAnimal()
	{
		Console.WriteLine("From animal");
	}
}

class Dog : Animal
{
	public override void ShowAnimal()
	{
		Console.WriteLine("From dog");
	}
}

Animal a = new Dog();
a.ShowAnimal();

public void ShowAnimal()
{
	Console.WriteLine("From dog");
}

class Animal {};
class Cat : Animal {};
class Dog : Animal {};

List<Animal>_myListOfAnimals = new List<Animal>();

Animal myCat = new Cat(); //assume Cat derived from Animal
Animal myDog = new Dog(); //assume Dog derived from Animal

_myListOfAnimals.Add( myCat );
_myListOfAnimals.Add( myDog );