Call by Value Call by Reference and Params Concept in C# .Net

Call by Value Call by Reference and Params Concept  in C# .Net...................

Call by value: In the call by value method, the called function creates a new set of variables in stack and copies the values of the arguments into them.

Example: Program showing the Call by Value method..........................

First we will create class which name is Class1 and defined method Swap with two no...

class Class1

{

public void Swap(int a, int b)

{

a = a + b;

b = a - b;

a = a - b;

MessageBox.Show("Swapped values are a = " + a + "and b = " + b);

}

}

Then we will take a Window From with two TextBox ………………………………

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Windows.Forms;

namespace CallByValueandReference

{

public partial class Form1 : Form

{

public Form1()

{

InitializeComponent();

}

int a, b;

Class1 cc = new Class1();

private void btnswap_Click(object sender, EventArgs e)

{

a = Convert.ToInt32(textBox1.Text);

b = Convert.ToInt32(textBox2.Text);

MessageBox.Show("Original values are a = "+ a +"and b="+ b);

cc.Swap( a,  b);

MessageBox.Show("The values after swap are a = " + a + "and b =" + b);

}

}

}

Output:

Call by reference: In the call by reference method, instead of passing values to the function being called, references/pointers to the original variables are passed.

Example: Program showing the Call by Reference method.........................

First we will create class which name is Class1 and defined method Swap with two no.........

class Class1

{

public void Swap(ref int a , ref  int  b)

{

a = a + b;

b = a - b;

a = a - b;

MessageBox.Show("Swapped values are a = " + a + "and b = " + b);

}

Then we will take a Window From with two TextBox ………………………………

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Windows.Forms;

namespace CallByValueandReference

{

public partial class Form1 : Form

{

public Form1()

{

InitializeComponent();

}

int a, b;

Class1 cc = new Class1();

private void btnswap_Click(object sender, EventArgs e)

{

a = Convert.ToInt32(textBox1.Text);

b = Convert.ToInt32(textBox2.Text);

MessageBox.Show("Original values are a = "+ a +"and b="+ b);

cc.Swap(ref  a ,ref  b);

MessageBox.Show("The values after swap are a = " + a + "and b =" + b);

}

}

}

Output:

What is Params : its enables methods to receive variable numbers of parameters. With params, the arguments passed to a method are changed by the compiler to elements in a temporary array. In other way we can say you are not assured about number of parameters or you want to create a method that can accept n number of parameters at run time. This situation can be handled with params type array in C#. The params keyword creates an array at run time that receives and holds n number of parameters.

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Windows.Forms;

namespace CallByValueandReference

{

public partial class Form2 : Form

{

public Form2()

{

InitializeComponent();

}

class Class1

{

// params concept in C# .net

public int sum(params int[] arr)

{

int total = 0;

foreach (int a in arr)

total += a;

return total;

}

}

private void button1_Click(object sender, EventArgs e)

{

Class1 cc = new Class1();

int res = cc.sum(2, 8, 9, 08, 34, 23);

MessageBox.Show(res.ToString());

}

}

}

Output: