Java实现二分查找详解编程语言

public class BinarySearch {  
        /**  
        * 二分查找算法  
        *  
        * @param srcArray 有序数组  
        * @param key 查找元素  
        * @return key的数组下标，没找到返回-1  
        */   
        public static void main(String[] args) {  
            int srcArray[] = {3,5,11,17,21,23,28,30,32,50,64,78,81,95,101};    
            System.out.println(binSearch(srcArray, 0, srcArray.length - 1, 81));   
        }  
 
        // 二分查找递归实现    
        public static int binSearch(int srcArray[], int start, int end, int key) {    
 
            int mid = (end - start) / 2 + start;    
            if (srcArray[mid] == key) {    
                return mid;    
            }    
            if (start >= end) {    
                return -1;    
            } else if (key > srcArray[mid]) {    
                return binSearch(srcArray, mid + 1, end, key);    
            } else if (key < srcArray[mid]) {    
                return binSearch(srcArray, start, mid - 1, key);    
            }    
            return -1;    
        }  
 
        // 二分查找普通循环实现    
        public static int binSearch(int srcArray[], int key) {    
            int mid = srcArray.length / 2;    
            if (key == srcArray[mid]) {    
                return mid;    
            }    
 
            int start = 0;    
            int end = srcArray.length - 1;    
            while (start <= end) {    
                mid = (end - start) / 2 + start;    
                if (key < srcArray[mid]) {    
                   end = mid - 1;    
                } else if (key > srcArray[mid]) {    
                    start = mid + 1;    
                } else {    
                    return mid;    
                }    
            }    
            return -1;    
        }  
    }