what does upcasting/downcasting even do??

Question

im just completely confused as to what it does. what the hell is its functionality

Answer 1

casting is used to change the type of a value. upcasting changes the value to a more complex type (e.g. integer to double). downcasting change the value to a simpler type (e.g double to integer)

Answer 2

Up casting : in casting, if you cast parent class reference to child class is called up-casting.. Or also casting from lower type data type to upper datatype is also called up-casting..
Ex:
class A{
..
}
class B extends A{
...
}
Here,
A a=new A();
B b=new B();
b=(A) a; //upcasting, but not always possible..

int c=5;
double d=(double) c;

Down casting: just in reverse, casting child to parent is down casting..
Ex:
A aa=(B) b;
int i=(int) d; //here double d=1;

Hope this helps...

Edit: