medium_21_1.java

public static int binarySearch (int values[], int target) {
	int left = 0;
	int mid = 0;
	int right = values.length - 1;

	while (left <= right) {
		mid = (left + right) / 2;

		if (target == values[mid])
			return mid;
		else if(target > values[mid])
			left = mid + 1;
		else
			right = mid - 1;
	}
	return -1;
}