l82.cpp

《数据结构（C++描述）》-李根强-源代码

//二分查找的实现
#include<iostream.h>
const   int  n=10 ;
typedef int elemtype;                            //n为表的最大长度
struct    node
{elemtype   key;                              //key为关键字，类型设定为elemtype
};
node R[n+1]={0,2,4,6,8,11,13,15,17,20,29};
int    binsearch(node    R[n+1],    elemtype   k)
{      int     low=1,     high=n;
 while (low<=high)
{     int  mid=(low +high)/2;                           //取区间中点
if(R[mid].key==k)
   return    mid;      //查找成功
else if(R[mid].key>k)
      high=mid-1;                                      //在左子区间中查找
else    low=mid+1;                                 //在右子区间中查找
}
return    0;                                            //查找失败
}


void main()
{ int k,j;
cout<<"线性表为:"<<endl;
for(j=1;j<=n;j++) cout<<R[j].key<<"  ";
cout<<endl<<"请输入待查元素";
cin>>k;
j=binsearch(R,k);
cout<<endl<<"待查元素"<<k<<"的位置为:"<<j<<endl;
}