检索之二分检索

上代码：

#include <iostream>
#include <vector>
using namespace std;
 
class Item
{
private:
    int Key;
public:
    Item(int value):Key(value){}
    int getKey()
    {
       return Key;
    }
    void setKey(const int &K)
    {
       this->Key = K;
    }
};
 
int BinSearch(vector<Item *> &dataList, int length, const int &K)
{
  int low = 0 ;
  int high = length;
  int mid;
  while(low <= high)
  {
    mid = (low + high)/2;
    if(K < dataList[mid]->getKey())
    {
      high = mid -1;
    }
    else if(K > dataList[mid]->getKey())
    {
      low = mid +1;
    }
    else
    {
      return mid;
    }
 }
    return 0;
 }
 
int main()
{
  vector<Item *> datalist;
  int key;
  int fn;
  int ifn;
  cout<<"input the key : "<< endl;
  cin>> key;
  while(key >= 0)
  {
      datalist.push_back(new Item(key));  
      cin>> key;
  }
  int len = datalist.size();
  cout<< "The datalist size is :" <<endl;
  cout<< len << endl;
  cout<< "input the key value to be found : "<<endl;
  cin>> ifn;
  fn=BinSearch(datalist, len, ifn);
  cout<< "The position index is : " << endl;
  cout<<fn<<endl;
  for(vector<Item *>::iterator it= datalist.begin(); it!=datalist.end(); it++)
      delete *it;
 
     
  return 0;
 }