Writing generic array class

[aqeel2010]

Hello my friends, I have assignment to he write generic array class include the following methods:

. no argument constructor
. copy constructor
. PushFront()
.PushBack()
. PopFront()
PopBack()
. Insert()
. Delete()
.GetAt()
.find()

and I have no Idea how to start. Please any suggestion to start, or any material that will help me to understand the assignment.


Thanks

[JosAH]

Arrays and generics don't go well together; better encapsulate a List<T> in your class because it has most (all?) of those methods available; all your class has to do then is delegate to those methods.

kind regards,

Jos

[j2me64]

Arrays and generics don't go well together

Right, but the ot means perhaps something like

public class GenericClass <T> {
	List<T> list = new ArrayList<T>();
	
	public void add(T t) {
		list.add(t);
	}
	// other methods

where the class GenericClass can be instantiated with any class and then this instance is type safe for the used class in the instantiation.

[JosAH]

Right, but the ot means perhaps something like

public class GenericClass <T> {
	List<T> list = new ArrayList<T>();
	
	public void add(T t) {
		list.add(t);
	}
	// other methods

where the class GenericClass can be instantiated with any class and then this instance is type safe for the used class in the instantiation.

Yep, that's what I also suggested in my reply.

kind regards,

Jos

[aqeel2010]

The assignment is to implement a generic array class and generic linked linst class and liked list nod class.

[aqeel2010]

Thanks a lot guys for this helpful discussion

[aqeel2010]

I have writtin the class , and I hope it works as it should. The problem know is that how to push 200000 elements to the array. I have tried small numbers. Know I need help in how to using pushFront() for these 200000 elements.

public class GenericArray<E  >{
	
	//private int   size; 
	private E[] items; 
	
	public GenericArray(){
		
		this.items = (E[])new Object[0];
		
	}
	
	public GenericArray(E []ga){
	
		this.items = (E[])new Object[ga.length];
		for (int i=0; i<ga.length;i++){
			this.items[i]=ga[i];
		}
	}
	
	public void pushFront(E item){
		E[] newItems = (E[])new Object[items.length+1];
		for(int i=1; i<newItems.length; i++){
			newItems[i] = items[i-1];
		}
		newItems[0]=item;
		this.items = newItems;
	}
	
	public void pushBack(E item){
		E[] newItems = (E[])new Object[items.length+1];
		for (int i=0; i<items.length; i++){
			newItems[i] = items[i];
		}
		newItems[newItems.length-1] = item;
		this.items = newItems;
	}
	
	public E   popFront(){
		E item=items[0];
		this.delete(0);
		return item;
	}
	
	public E popBack(){
		
		E item = items[items.length-1];
		this.delete(items.length-1);
		return item;
	}
        public void insert(E item, int index){
        	E[] newItems = (E[]) new Object[items.length+1];
        	//E newItems[] = new E [size+1];
        	for(int i =0; i<index; i++){
        		newItems[i] = items[i];	
        	}
        	 newItems[index]= item;
        	 for(int i = index+1; i<items.length+1; i++ ){
        		 newItems[i] = items[i-1];  
        	 }
        	this.items = newItems;
        }
        
        
        
        public void delete(int index){
        	E[] newItems = (E[]) new Object[items.length-1];	
        //E newItems [] = new E [size-1];
        	
        	for (int i = 0; i <index; i++ ){
        		newItems[i] = items[i];
        	}
        	
        	for (int i = index+1; i<items.length; i++ ){
        		newItems[i-1] = items[i];
        	}
        	this.items = newItems;
        }
        
        public E getAt(int index){
        	 E item = items[index];
        	 return item;
        }
        
        
        public int find(E item){
        	int index ;
        	for (int i = 0 ; i<items.length; i++){
        		if (item == items[i]){		
        		  index=i;
        		  return index;
        		}
        	}
        	return -1;
        }
        
		
		public int getSize(){
			return this.items.length;
		}
	
	
	
	
	
	
}

also, here is the main class for the experiments

public class ExpermintsDemo {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		
		GenericArray <Integer>gaa = new GenericArray<Integer>();
		//GenericArray gaa = new GenericArray();
		gaa.pushFront(0);
		//gaa.pushFront();
		gaa.pushBack(7);
                gaa.popFront();
                gaa.insert(1,1);
		
		for (int i=0; i<gaa.getSize(); i++)
		{
			System.out.print(gaa.getAt(i));
		}
		
                  //GenericArray <Integer>strArr = new GenericArray<Integer>();
		//int i;
		//for ( i = 0; i<2;i++){
		
		
	         // strArr.insert(1, 1);
		//strArr.insert(2, 2);
		// strArr.pushFront(0);
                //  strArr.popFront();
             //  strArr.popFront();
                //System.out.println(strArr.pushFront());
		 // System.out.println(i);
                 
		
		}
                  
		
	
		
		
		//System.out.println(strArr.popBack());
		 
		
		
		
		// TODO Auto-generated method stub

	}

please guys any help wit figuring out this project

I am new to java