java数组中根据元素查找位置 索引-ag真人游戏

    public static void main(string[] args) {
        // todo auto-generated method stub
        string[] arrays = new string[]{"a","b","c","d","e","fff","g","h","i","j",};
        int positon = arrays.binarysearch(arrays, "fff");  
         system.out.println("position is:" positon);
    }

测试结果：

    position is:5  

这个方法也是用的二分法实现的：

    public static int binarysearch(char[] array, int startindex, int endindex, char value) {  
            checkbinarysearchbounds(startindex, endindex, array.length);
      
            int lo = startindex;  
            int hi = endindex - 1;  
      
            while (lo <= hi) {  
                int mid = (lo   hi) >>> 1;//无符号右移  
                char midval = array[mid];  
      
                if (midval < value) {  
                    lo = mid   1;  
                } else if (midval > value) {  
                    hi = mid - 1;  
                } else {  
                    return mid;  // value found  
                }  
            }  
            return ~lo;  // value not present  
        }