Introduction

A constructor is a special method of a class which is used to intialize the data members of the class. Constructor is a special type of method, which will be executed automatically while creating an object. Destructor is a special type of method, which will be executed automatically while destroying an object. Some of main features of contructor are,

• It is a sub procedure declared with the new keyword.
• It doesn't return any value.
• A class can have multiple constructors
• It doesn't mandatory to declare a constructor, the compiler invokes it automatically

Differences between constructor and destructor

Constructor	Destructor
Constructor is a special type of method, executed automatically while creating an object.	Destructor is a special type of method, executed automatically while destroying an object.
Constrctor name must be same as class name without any return type.	Destructor name must be same as class name with a ~(tild) prefix and without any return type and access specifier.
Constructors are overloadable.	Destructors are not overloadable.
Generally constructors are required while initializing instance variables, to open files or to open database connections.	Generally destructors are used to deallocate the memory or to close the files or to close database connections.

Example on constructor and destructor along with garbage collector concepts:

    class Test
{
    public Test()
    {
        MessageBox.Show("From Constructor");
    }
    ~Test()
    {
        MessageBox.Show("From Destructor");
    }
}
private void button1_Click(object sender, EventArgs e)
{
    Test t1 = new Test();
    Test t2 = new Test();
    Test t3 = new Test();
}

Observation:

• Here in the above program constructor executed for 3 times destructor also executed for 3 times.
• Destructor will be executed after the project is closed.
• After destructor is executed then within two seconds garbage collector will be loaded into the memory.
• Garbage collector reclaim|deallocate|free the memory allocated for the current project.
• Garbage collector will be done with the help of a predefined class called as System.GC