C#

class myClass
{
	// fields
	private string _name;
	private double[] _number = new double[5];
	
	// properties
	public string name
	{
		get { return _name; }
		set { _name = value; }
	}
	
	public double[] number
	{
		get { return _number; }
		set { _number = value; }
	}
	
	public double this[int index]
	{
		get { return _number[index]; }
		set { _number[index] = value; }
	}
	
	// Default constructor:
	public myClass()
	{
		name = "";
		_number[0] = 0;
		_number[1] = 0;
		_number[2] = 0;
		_number[3] = 0;
		_number[4] = 0;
	}
	// Clear Numbers
	public void ClearNumbers()
	{
		_number[0] = 0;
		_number[1] = 0;
		_number[2] = 0;
		_number[3] = 0;
		_number[4] = 0;
	}
}

myClass foo = new myClass();

double firstElement = foo.number[0];

double firstElement = foo[0];

abdelhameed81 wrote:

how to use constructors

public class A 
{
    private string myText;

    public A(string someText)
    {
        this.myText = someText;
    }
 
    public void WriteMyText()
    {
        Console.WriteLine(someText);
    }
}

public class Program
{
    public static void Main()
    {
        A a = new A("Hello World");
        a.WriteMyText();
    }
}

abdelhameed81 wrote:

why do we use them regarding the idea that we can initialize our variables in any section without using constructors.

Colin Angus Mackay wrote:

The CLR will initialise the fields to default values if you don't set them. e.g. an int will be set to 0, a string to "" and so on.

bool blnValidUser = false ;<br />
<br />
bool LoginUser( string strUserName, string Password )<br />
{<br />
  if( username and password match )<br />
  {<br />
    blnValidUser = true ;<br />
    return true ;<br />
  }<br />
  else<br />
  {<br />
    blnValidUser = false ;<br />
    return false ;<br />
  }<br />
}<br />
<br />
void function1()<br />
{<br />
  if( blnValidUser is true )<br />
  {<br />
    Go ahead as planned.<br />
  }<br />
  else<br />
  {<br />
    return ;<br />
  }<br />
}