writing methods
===============


Exercise 1
----------

Write a method called sum, that
  - takes two integer arguments
  - returns the sum of the two integer aguments

public int sum(int a, int b) {
   return a + b;
}


Exercise 2
----------

Write a method call vat that

 - takes the net price as argument (a double)
 - returns the price including VAT (which is 20% in Italy)

public double vat(double price) {
   double tax = (20.0 / 100.0) * price;
   return price + tax;
}

  // example:
  // double netprice = 100.0;
  // double price;
  // price = vat(netprice);
  

Exercise 3
----------

write just a method that:

  - takes an array of integers as its argument

  - returns a new array of integers with all the
    elements of the argument array in REVERSED order

Example:

 if a[] contains 1, 2, 3, 4 and I pass a[] to this
 method, I'll get back another array that contains
 4, 3, 2, 1.


public int[] reverse(int[] a) {

   int size = a.length;
   int b[] = new int[size];

   int finger = 0;        // start copying from a[0]
   int pen = size - 1;    // start assigning to b[size -1]

   while(pen >= 0) {
       b[pen] = a[finger];
       finger++;   // add 1 to finger
       pen--;      // subtract 1 from pen
   }

   return b;
}