Vector class

assignment.java

public class Assignments {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		
		// create the vector
		Vector v = new Vector(200);
		
		// add 1 to 100 to the vector
		for(int i=0; i<100; i++) {
			v.addLast(i+1);
		}
		
		// get the size of the vector
		System.out.println("Size = " + v.size());
		
		// check for 6 and 101
		System.out.println("Contains 6 = " + v.contains(6));
		System.out.println("Contains 101 = " + v.contains(101));
		
		// get the first element
		System.out.println("First element = " + v.getFirst());

		// get the last element
		System.out.println("Last element = " + v.getLast());
		
		// print all contents of vector
		for(int i=0; i<v.size(); i++) {
			System.out.print(v.get(i) + " ");
		}
		System.out.println("");
		
		// add an element to the beginning of the vector
		v.addFirst(666);
		
		// print all contents of vector
		for(int i=0; i<v.size(); i++) {
			System.out.print(v.get(i) + " ");
		}
		System.out.println("");	
		
		// remove the first element
		v.removeFirst();

		// print all contents of vector
		for(int i=0; i<v.size(); i++) {
			System.out.print(v.get(i) + " ");
		}
		System.out.println("");			
		
		// remove the last element
		v.removeLast();
		
		// print all contents of vector
		for(int i=0; i<v.size(); i++) {
			System.out.print(v.get(i) + " ");
		}
		System.out.println("");	
		
		// reverse the vector
		v.reverse();
		
		// print all contents of vector
		for(int i=0; i<v.size(); i++) {
			System.out.print(v.get(i) + " ");
		}
		System.out.println("");		
		
		// duplicate & double
		v.duplicate();
		
		// print all contents of v
		for(int i=0; i<v.size(); i++) {
			System.out.print(v.get(i) + " ");
		}
		System.out.println("");	

	}
}

vector.java

public class Vector {
	protected Object data[];
	protected int count;
	
	
	// create a vector with a fixed capacity
	public Vector(int capacity) {
		data = new Object[capacity];
		count = 0;
	}

	public Vector duplicate() {
		Vector result = new Vector(count*2);

		for (int i = 0; i < count; i++) {
			result.addLast(data[i]);
			result.addLast(data[i]);
		}

		return result;
	}
	
	// read the data from an element
	public Object get(int index) {
		return data[index];
	}
	
	// get the first element of the vector
	public Object getFirst() {
		return data[0];
	}
	
	// get the last element of the vector
	public Object getLast() {
		return data[count-1];
	}	
	
	// add an element to the beginning of the vector
	public void addFirst(Object item) {
		for(int i=count; i>0; i--) {
			data[i] = data[i-1];
		}
		data[0] = item;
		count++;
	}	
	
	// add an element to the end of the vector
	public void addLast(Object o) {
		data[count] = o;
		count++;
	}
	
	// overwrite an element
	public void set(int index, Object obj) {
		data[index] = obj;
	}
	
	// return size of vector
	public int size() {
		return count;
	}
	
	// check if vector is empty
	public boolean isEmpty() {
		return size() == 0;
	}
	
	// check if vector contains element
	public boolean contains(Object obj) {
		for(int i=0; i<count; i++) {
			if (data[i].equals(obj)) return true;
		}
		return false;
	}
	
	// quickly search for a value within the vector
	public boolean binarySearch(Object key) {
		int start = 0;
		int end = count - 1;
		
		while(start <= end) {
			int middle = (start + end + 1) / 2;
			if(key < data[middle]) end = middle - 1;
			else if(key > data[middle]) start = middle + 1;
			else return true;
		}
		return false;
	}
	
	// remove the first element
	public void removeFirst() {
		data[0] = null;
		for(int i=0; i<count; i++) {
			data[i] = data[i+1];
		}
		count--;
	}	
	
	// remove the last element
	public void removeLast() {
		data[count-1] = null;
		count--;
	}
	
	// reverse the vector, using data[count] as swap element
	public void reverse() {
		for(int i=0; i<(count/2); i++) {
			data[count] = data[i];
			data[i] = data[count-i-1];
			data[count-i-1] = data[count];
		}		
		data[count] = null;
	}
}