java之二分法查找

         //二分法查找
        //必须有序数组
        int [] erfen=new int[] {-50,0,1,10,56,105,160,250,1000,1500};
        int dest1=160;//以160为例
        int head=0;
        boolean isflag=true;
        int end=erfen.length-1;
        while(head<=end) {
            int middle =(head+end)/2;
            if(dest1==erfen[middle]) {
                System.out.println("找到了位置为"+middle);
                isflag=false;
                break;
            }
            else if(dest1