#include <stdio.h>       int bin_search(int key[],int low, int high,int k)      {        int mid;        if(low>high)     {        return -1;        }     else       {             mid = (low+high) / 2;             if(key[mid]==k)                 return mid;             if(k>key[mid])                 return bin_search(key,mid+1,high,k);        /*在序列的后半部分查找*/             else                 return bin_search(key,low,mid-1,k);            /*在序列的前半部分查找*/          }     }     int main()     {         int n , i , addr;         int A[10] = {2,3,5,7,8,10,12,15,19,21};          printf("The contents of the Array A[10] are\n");          for(i=0;i<10;i++)           printf("%d ",A[i]);                                /*显示数组A中的内容*/          printf("\nPlease input a interger for search\n");          scanf("%d",&n);                                /*输入待查找的元素*/          addr = bin_search(A,0,9,n);          if(-1 != addr)    /*查找成功*/     {          printf("%d is at the %dth unit is array A\n ",n,addr);     }       else  {   printf("There is no %d in array A\n",n);            /*查找失败*/     }   getchar();      return 0;      }