Knapsack greedy algorithm

knapsack.java

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.*;
public class knapsack {


	public static void main(String[] args){

		BufferedReader reader=new BufferedReader(new InputStreamReader(System.in));
		int realtarget=0;
		int [] items=new int[5];
		int[] result;
		try{
			for(int i=0; i<5; i++)
			{

				System.out.println("Enter Weight"+(i+1)+":  ");
				items[i]=Integer.parseInt(reader.readLine());
			}	

			for(int i=0; i<5; i++)
				System.out.println("Value at "+(i+1)+" is  :"+items[i] );

			System.out.print("Enter Target Value");
	        	realtarget=Integer.parseInt(reader.readLine());
		}
		catch(IOException io)
		{
			System.out.println(io);
		}

		System.out.println("Target Value is: "+realtarget);

	    	result = knapSack(items, realtarget, 0, 0);

	    	if(result == null)
	    		System.out.println("Couldnt Find a solution");
	    	else
	    		for(int j=0; j < result.length; j++)
	    			System.out.println(result[j]);

	}

	// This function takes an array of items and a knapsack size. It attempts to
	// fill the knapsack exactly with the given items. It only considers items
	// in the array that are in slots first, first+1,... So when the function
	// is initially called it should be called with first equal to 0.
	// In addition the function also takes as input the size of the current
	// (partial) solution. This is initially 0.

	public static int[] knapSack(int[] items, int realtarget, int first, int solutionSize){

		if(realtarget > 0)
		{
			// For each i, try placing the ith item in the knapsack
			for(int i= first; i < items.length; i++)
			{
				// Fit the smaller knapsack with items chosen from i+1, i+2,...
				int [] answer = knapSack(items, realtarget-items[i], i+1, solutionSize+1);

				if (answer != null)
				{
					answer[solutionSize] = items[i];
					return answer;
				}
			}

			return null;
		}
		// We have found a solution. So we create an array of the right size
		// and send it back for filling
		else if(realtarget==0)
		{
			int[] temp = new int[solutionSize];
			return temp;
		}
		
		else // realtarget is negative, so no solution is possible
			return null;

	}

}