二分探索 while版

binarySearch.java

int binarySearch(int[] array, int x){
	int low = 0;
	int high = array.length-1;
	int mid;
	
	while (low <= high) {
		mid = (low + high) / 2;
		if(array[mid]< x){
			low = mid + 1;
		}else if(array[mid] > x){
			high = mid - 1;
		}else {
			return mid;
		}
		
	}
	return -1;
}