binsearch.java

JAVA编程思想源代码 值得一下 很难找的

package chapter5;

public class BinSearch {

	public static void main(String[] args) {
		int a[] = { 1, 3, 5, 6, 7, 8, 9, 23, 34, 45, 46, 67 };
		int index = -1, left = 0, mid = -1, right;
		right = a.length;
		int num = 46;
		while (left <= right) {
			mid = (left + right) / 2;
			if (a[mid] == num) {
				index = mid;
				break;
			} else if (a[mid] < num)
				left = mid + 1;
			else if (a[mid] > num)
				right = mid - 1;
		}
		if (index == -1)
			System.out.println("数字" + num + "不在数组中！");
		else
			System.out.println("数字" + num + "在数组中的位置是：" + index);
	}
}