有序表的二分查找和伪代码

int Binary_Search(int *a, int n, int key)
{
  int mid = 0;
  int high = n-1;
  int low = 0;
  while (low <= high)
  {
      mid = (low+high)/2;
      if(key < a[mid])
      {
          high = mid-1;
      }
      else if (key > a[mid])
      {
          low = mid+1;
      }
      else if (key == a[mid])
      {
          return mid;
      }
  }
  return -1;//查找失败
}

int main()
{
    int a[10] = {1,2,3,4,5,6,7,8,9,10};
    int key = 7;
    cout<<Binary_Search(a, 10, key)<<endl;
    key = 99;
    cout<<Binary_Search(a, 10, key)<<endl;//如果返回-1，则查找失败
    getchar();
    return 0;
}

伪代码：

BinarySearch(max,min,des)

mid-<(max+min)/2

while(min<=max)

mid=(min+max)/2

if mid=des then

return mid

elseif mid >des then

max=mid-1

else

min=mid+1

return max