对有序数组进行二分查找（折半查找）

C code:

 void Bin_Search(int a[], int key)
{
     int left = 0;
     int right = MAX-1;
     int mid = 0;
     //折半查找 
     while(left <= right){
         mid = (left + right) / 2;
         if ( key==a[mid] )
            printf("你所查找的数在数组中的位置是：%d\n", mid);
        else if( key<a[mid] )
            right = mid-1;
        else left = mid+1;
    }
    if (left > right)
        printf("您所要查找的数不在该数组。\n");
}