package rebelsky.exam2;

import java.math.BigInteger;
import rebelsky.io.Pen;

/**
 * A moderate test of binary search.  Build an array containing the even
 * values between 0 and 32, inclusive.  Search for all values between
 * -1 and 33.  Even numbers have an index of half of their value.  Odd
 *  numbers should not be in the array.
 */
public class TestBinarySearch
{
	public static void main(String[] args)
	{
		int SIZE = 17; // The size of the array
		Pen pen = new Pen();
		int errors = 0;	// How many errors we've observed.

		// Prepare the array to search
		BigInteger[] evens = new BigInteger[SIZE];
		for (int i = 0; i < SIZE; i++) {
			evens[i] = BigInteger.valueOf(2*i);
		} // for

		// Create the searcher.
		BinarySearcher bs = new BinarySearcher(new BigIntegerComparator());

		// Make sure all the evens work correctly.
		for (int i = 0; i < 2*SIZE; i += 2) {
			try {
				int pos = bs.binarySearch(BigInteger.valueOf(i), evens);
				if (i != pos*2) {
					pen.println(i + " incorrectly appeared at position " + pos);
					++errors;
				}

			}
			catch (Exception e) {
				pen.println(i + " was incorrectly reported as being missing ");
				++errors;
			} // catch(Exception)
		} // for

		// Make sure all the odds work correctly.
		for (int i = -1; i < 2*SIZE + 2; i += 2) {
			try {
				int pos = bs.binarySearch(BigInteger.valueOf(i), evens);
				pen.println(i + " incorrectly appeared at position " + pos);
				++errors;
			}
			catch (Exception e) {
				// Yay!  We wanted an exception.
			}
		} // for

		if (errors == 0)
			pen.println("All tests succeeded.");
		else
			pen.println("Found " + errors + " errors.");
	} // main(String[])
} // class TestBinarySearch