C# 4.0 Feature - Optional Arguments

The feature that we are discussing today is called as “Optional Arguments”. Prior to C#4.0, whenever we need to pass optional parameters for a method, we used to use method overloading . For eg:
private int Add(int i)
{
return i + 2;
}

Now if the Add method wanted to accept two parameters then we used to write as follows
private int Add(int i, int j)
{
return i + j;
}

Now if the Add method wanted to accept two parameters then we used to write as follows
private int Add(int i, int j, int k)
{
return i + j + k;
}

Eventually we had to write three overloaded methods based on the number of parameters passed and invoke the method based on the parameters passed.
In C#4.0, we can rewrite the code by declaring parameters as optional as follows
private int Add(int i, int j = 1, int k = 0)
{
return i + j + k;
}

When invoking this method and need only one parameter to be passed use it as follows
private void button1_Click(object sender, EventArgs e)
{
MessageBox.Show(Add(2).ToString());
}

In this case the result will be show as 3 since for “i” we passed 2 , the default for “j” is 1 and the default for “k” is 0. If we were to pass 2 parameters it would be as follows
private void button1_Click(object sender, EventArgs e)
{
MessageBox.Show(Add(2, 3).ToString());
}

Now the result would be 5, since for “i” we passed 2, for “j” we passed 3 and the default for “k” is 0.

Hope this was cool feature. Please add your comments or suggestions.

Cheers!!!