What is the purpose of accessors?

Question

Can somebody help me understand the get & set?
Why are they needed? I can just make a public variable.

Answer 1

get{} and set{} are accessors that offer up the ability to easily read and write to private fields. Working with a simple example:

public class Foo()
{ 
    //Field
    private int _bar;

    //Property
    public int Bar
    {
        get { return _bar; }
        set { _bar = value; }  
        //value is an implicit parameter to the set acccessor.
        //When you perform an assignment to the property, the value you
        //assign is the value in "value"
    }
}

In this case, Bar is a public property that has a getter and a setter that allows access to the private field _bar that would otherwise be inaccessible beyond class Foo.

Now in a class that has an instace of Foo, you can do this:

public class IHasAFoo()
{
    private Foo _myFoo = new Foo();

    public void SomeMethod()
    {
        _myFoo.Bar = 42;
    }
}

So the public accessor allows you to set the value of the private field back in Foo.

Hope that helps!