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SkyView.java

public class SkyView {
	/** A rectangular array that holds the data representing a rectangular area of the sky. */ 
	private double[][] view;

	/**Constructs a SkyView object from a 1-dimensional array of scan data.
	 *  @param numRows the number of rows represented in the view
	 *  Precondition: numRows > 0
	 *  @param numCols the number of columns represented in the view
	 *  Precondition: numCols > 0
	 *  @param scanned the scan data received from the telescope, stored in telescope order
	 *  Precondition: scanned.length == numRows * numCols 
	 *  Postcondition: view has been created as a rectangular 2-dimensional array
	 *  with numRows rows and numCols columns and the values in 
	 *  scanned have been copied to view and are ordered as
	 *  in the original rectangular area of sky.
	 */
	public SkyView(int numRows, int numCols, double[] scanned) 
	{
		/* to be implemented in part (a) */

	}
	/**Returns the average of the values in a rectangular section of view.
	 * @param startRow the first row index of the section
	 * @param endRow the last row index of the section
	 * @param startCol the first column index of the section
	 * @param endCol the last column index of the section
	 * Precondition: 0 <= startRow <= endRow < view.length
	 * Precondition: 0 <= startCol <= endCol < view[0].length
	 * @return the average of the values in the specified section of view
	 */
	public double getAverage(int startRow, int endRow, int startCol, int endCol)
	{ 
		/* to be implemented in part (b) */ 

	    return 0;
	}
	// There may be instance variables, constructors, and methods that are not shown
	public double[][] getView(){
		return this.view;
	}
	public  String toString(){
		String result="  ";
		for(int i=0; i<view[0].length;i++)
			result+=String.format("%3d  ", i);
		result+="\n";
		for(int i=0; i<view.length;i++){
			result+=i+" ";
			for(double d:view[i])
				result+=String.format("[%3.1f]", d);
			result+="\n";
		}
		return result;
	}
}

SkyViewTester.java

public class SkyViewTester {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		double[] scanned1 = {0.3, 0.7, 0.8, 0.4, 1.4, 1.1, 0.2, 0.5, 0.1, 1.6, 0.6, 0.9};
		printArray(scanned1);
		double[] scanned2 = {0.3, 0.7, 0.8, 0.4, 1.4, 1.1};
		SkyView sv1 = new SkyView(4,3,scanned1);
		if(sv1.getView()==null){
			System.out.println("Your constructor returned a null");
		}else {

			System.out.println("\nSkyView Example 1:");
			System.out.println(sv1);
			String expected = "    0    1    2  \n0 [0.3][0.7][0.8]\n1 [1.1][1.4][0.4]\n2 [0.2][0.5][0.1]\n3 [0.9][0.6][1.6]\n";
			if(sv1.toString().equals(expected))
				System.out.print("No ");
			System.out.println("problems found.\n");

			printArray(scanned2);
			System.out.println("\nSkyView Example 2:");
			SkyView sv2 = new SkyView(3,2,scanned2);
			System.out.println(sv2);
			expected = "    0    1  \n0 [0.3][0.7]\n1 [0.4][0.8]\n2 [1.4][1.1]\n";
			if(sv2.toString().equals(expected))
				System.out.print("No ");
			System.out.println("problems found.\n");

			System.out.print("\nSkyView Part B:\n getAverage(1, 2, 0, 1) should return 0.8\nYour returns ");
			System.out.println(sv1.getAverage(1, 2, 0, 1));
		}
	}
	public static void printArray(double[] a){
		for(int i=0; i<a.length;i++)
			System.out.print(String.format("%3d  ", i) ) ;
		System.out.println();
		for(double d:a)
			System.out.print( String.format("[%3.1f]", d));
		System.out.println();
	}

	public static String toString(double[][] a){
		String result="  ";
		for(int i=0; i<a[0].length;i++)
			result+=String.format("%3d  ", i);
		result+="\n";
		for(int i=0; i<a.length;i++){
			result+=i+" ";
			for(double d:a[i])
				result+=String.format("[%3.1f]", d);
			result+="\n";
		}
		return result;
	}
}