binaryseach.java

java数据结构,简单,易懂,有利于初学者

class BinarySearch
{
	public static void main(String args[])
	{
		int[] numbers={1,3,4,8,9,12,13,17,18,23,42,49,99,100};
		System.out.println(indexOf(numbers,14));
	}
	static int indexOf(int[] arr,int value)
	{
		int start=0;
		int end=arr.length-1;
		int middle=(start+end)/2;
		while(start!=end)
		{
			if(value<arr[middle])
			{
				end=middle-1;
			}
			else
			{
				start=middle+1;
			}
			middle=(start+end)/2;
		}
		if(arr[start]==value)
		{
			return start;
		}
		else
		{
			return -1;
		}
	}
}