Difference between override and new

the keyword "new" doesn't change the base class method, while the keyword "override" changes.

We have these code:


class Program
{
static void Main(string[] args)
{
DerivedClass dc = new DerivedClass();
BaseClass bc = new DerivedClass() as BaseClass;

dc.Print();
bc.Print();
}
}

public abstract class BaseClass
{
public virtual void Print()
{
Console.WriteLine("This is base class");
}
}

public class DerivedClass : BaseClass
{
public new void Print()
{
Console.WriteLine("This is derived class");
}
}
The running results are:
This is derived class
This is base class

while if we wrote code below:
class Program
{
static void Main(string[] args)
{
DerivedClass dc = new DerivedClass();
BaseClass bc = new DerivedClass() as BaseClass;

dc.Print();
bc.Print();
}
}
public abstract class BaseClass
{
public virtual void Print()
{
Console.WriteLine("This is base class");
}
}

public class DerivedClass : BaseClass
{
public override void Print()
{
Console.WriteLine("This is derived class");
}
}

The running results are:
This is derived class
This is derived class