C++二分法查找算法

/**************************************************************
*  二分法查找算法
*  wxz 2011-05-04
***************************************************************/
#include<iostream>
#define MaxSize 100
using namespace std;
typedef int DataType;

typedef struct ST
{
 DataType Data[MaxSize];
 int Length;
}ST;

void CreateST(ST *st)
{
  int i;
  cout<<"请输入要建立的顺序表的长度"<<"("<<MaxSize<<"以内)"<<endl;
  cin>>st->Length;
  while(st->Length>100)
  {
   cout<<"长度不能大于"<<MaxSize<<endl;
   cout<<"请输入要建立的顺序表的长度"<<"("<<MaxSize<<"以内)"<<endl;
   cin>>st->Length;
  }
  cout<<"请输入"<<st->Length<<"个整数："<<endl;
  for(i=0;i<=st->Length-1;i++)
  cin>>st->Data[i];

}

int BinarySearch(ST *st,DataType d)
{
 int low,high,mid;
 int count;
 int flag;
 low=0;
 count=1;
 flag=0;
 high=st->Length-1;
 while(low<=high)
 {
        mid=(low+high)/2;
        if (d<st->Data[mid])
  high=mid-1;
  else
   if(d>st->Data[mid])
    low=mid+1;
   else
   {
                flag=mid;
    break;
   }
   count++;
  
 }
 
 return flag;
}
int main()
{
  int idx;
  DataType d;
  ST *st=new ST; 
  CreateST(st); 
  cout<<"请输入要查找的元素：";
  cin>>d;
  idx=BinarySearch(st,d)+1;
  if(idx==0)
 cout<<"没有找到你要查找的元素。";
  else
 cout<<"所要查找的元素"<<d<<"的位置是"<<idx<<endl;
  return 0;
}

 

 

来源：CSDN

作者：xinzheng_wang

链接：https://blog.csdn.net/xinzheng_wang/article/details/6643239