/**
 * BinarySearch.java
 * <br>
 * A class to demonstrated iterative binary search on a sorted array.
 * <br>
 * Created: Tue Feb 11 14:30:59 2003
 *
 * @author <a href="mailto:shapiro@cse.buffalo.edu">Stuart C. Shapiro</a>
 */

public class BinarySearch {

    /**
     * Returns the index within the array a of the first occurrence of the int i,
     * or -1 if i does not occur in a.
     * <p> a is assumed to be sorted from lower to higher ints.
     *
     * @param a the sorted <code>int[]</code> to be searched.
     * @param i an <code>int</code> value to search for.
     * @return the index of the first occurrence of i in a,
     * or -1 if i does not occur in a.
     */
    public static int indexOf(int[] a, int i) {
	int min = 0;
	int max = a.length - 1;
	int mid;
	while (min <= max) {
	    // The search range is a[min .. max]
	    mid = (min + max) / 2;
	    if (i == a[mid]) return mid;
	    else if (i < a[mid]) max = mid-1;
	    else min = mid+1;}
	return -1;
    }

    /**
     * Tests the indexOf method.
     *
     */
    private static void test(int[] a, int i) {
	System.out.print(i + " is at position " + indexOf(a, i) + " of "
			 + "\t{" + a[0]);
	for (int j = 1; j < a.length; j++) {System.out.print(", " + a[j]);}
	System.out.println("}");
    }

    /**
     * Demonstrates iterative binary search.
     *
     * @param args a <code>String[]</code> value
     */
    public static void main (String[] args) {
	int[] testarray = {2,4,25,43,43,46,54,54,85,285,541,564};
	test(testarray, 54);
	test(testarray, 1);
	test(testarray, 99);
	test(testarray, 999);
    } // end of main ()
    
    
}// BinarySearch