Rename function Grow() to Resize(). The new version of this function takes an argument of type int called new_size. Instead of simply doubling the capacity of the vector, it sets the new capacity to the value passed in new_size, which is always expected to be equal or greater than field length. Modify function Insert() in a way that it calls the new function Resize(), instead of Grow(), and in a way that its behavior remains the same as before. This function should continue to print a message showing the new vector's capacity. Modify function Remove() in a way that it reduces the vector's capacity in half when its utilization is less than 50% of the allocated capacity, and when the resulting capacity would be at least 1 element. Write a main program in a separate file named Test.java in which you enter 5 elements and extract 4. While running the program, you should observe that the vector grows twice, and later shrinks twice, too.
This is a subclass and doesn't has a main method yet.
class
{
Object items[];
int length;
int size;
void Grow()
{
// Duplicate size
size = size * 2;
// Allocate new items
Object new_items[] = new Object[size];
// Copy old items
for (int i = 0; i < length; i++)
new_items[i] = items[i];
// Discard old items
items = new_items;
// Message
System.out.println("Growing capacity to " + size + " elements");
}
public Vector()
{
size = 2;
items = new Object[2];
}
public void Print()
{
// Message
System.out.println("Content:");
// Traverse
for (int i = 0; i < length; i++)
System.out.println(items[i]);
}
public void Insert(int index, Object item)
{
// Check index
if (index < 0 || index > length)
{
System.out.println("Invalid index");
return;
}
// Grow if necessary
if (length == size)
Grow();
// Shift
for (int i = length - 1; i >= index; i--)
items[i + 1] = items[i];
// Insert
items[index] = item;
// One more item
length++;
// Message
System.out.println("Inserted " + item);
}
public void Add(Object item)
{
Insert(length, item);
}
public void Remove(int index)
{
// Check index
if (index < 0 || index >= length)
{
System.out.println("Invalid index");
return;
}
// Message
System.out.println("Removing " + items[index]);
// Shift
for (int i = index; i < length - 1; i++)
items[i] = items[i + 1];
// One less item
length--;
}
public Object Get(int index)
{
return index >= 0 && index < length ?
items[index] :
null;
}
public int GetLength()
{
return length;
}
public void Swap(int index1, int index2)
{
Object temp = items[index1];
items[index1] = items[index2];
items[index2] = temp;
}
}
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