二分法（输入一组数，输入要找的数，看二分法需要几次找到）

import java.io.BufferedReader;
import java.io.InputStreamReader;

public class TwoFenOrder{

	public int[] inputInteger(){
		System.out.println("please input Integer......");
		String temp=null;
		try{
			BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
			temp = br.readLine();
		}catch(Exception e){
			e.printStackTrace();
		}

		final int count = temp.length();
		int[] intArray = new int[count];

		for(int i=0 ; i			intArray[i] = Integer.valueOf(temp.substring(i,i+1));
		}

		//二分法要求数组必须是有序的。(使用递归)
		int tmpInt=0;
		for(int i=0 ;i 			for(int j=i;j				if(intArray[i] > intArray[j]){
					tmpInt = intArray[j];
					intArray[j] = intArray[i];
					intArray[i] = tmpInt;
				}
			}
		}

		//输出排列之后的数组
		for(int i : intArray){
			System.out.print(i + " ");
		}

		return intArray;
	}

	public void twoOrder(int[] intArray){
		System.out.println("please input Integer findValue !!!!!!!!");
		String temp = null;
		try{
			BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
			temp = br.readLine();
		}catch(Exception e){
			e.printStackTrace();
		}

		final int count =intArray.length;

		//要寻找的值
		int findValue = Integer.valueOf(temp);

		//起始start索引
		int start = 0;

		//终了end索引
		int end = count-1;

		//比较索引
		int index = (start + end)/2;

		//二分法查找次数
		int sum = 0;

		while(true){
			if(intArray[index] < findValue){
				start = index;
				index = (start + end)/2;
				sum++;
			}else if(intArray[index] > findValue){
				end = index;
				index = (start + end)/2;
				sum++;
			}else if(intArray[index] == findValue){
				System.out.println("使用二分法查找的次数是：" + sum);
				break;
			}//如果输入没有怎么办那？
		}
	}

	public static void main(String[] args){
		TwoFenOrder twoFenOrder = new TwoFenOrder();
		int[] intArray = twoFenOrder.inputInteger();
		twoFenOrder.twoOrder(intArray);
	}
}