code：
#include<iostream>
using namespace std;
class person
{
string name;
int age;
public:
person(const char* n,int a):name(n),age(a){}
friend bool operator <(const person& a,const person& b)//运算符重载-比较年龄大小
{
return a.age<b.age;
}
friend bool operator >(const person& a,const person& b)//运算符重载-比较年龄大小
{
return a.age>b.age;
}
friend bool operator ==(const person& a,const person& b)//运算符重载-等于号
{
return a.age==b.age;
}
friend ostream& operator<<(ostream& o,const person& a)//运算符重载-输出
{
o<<a.name<<":"<<a.age<<endl;
}
};
person* bsearch(person* a,int n,const int age)//二分查找
{
if(n<=0) return NULL;
int mid=n/2;
person p("",age);
if(a[mid]==p) return a+mid;
if(p<a[mid]) return bsearch(a,mid,age);
else return bsearch(a+mid+1,n-mid-1,age);
}
person* bsearch2(person* a,int n,const int age)//二分查找
{
int b=0,e=n-1;
person t("",age);
while(b<=e)
{
int mid=(b+e)/2;
if(a[mid]==t) return a+mid;
if(t<a[mid]) e=mid-1;
else b=mid+1;
}
return NULL;
}
int main()
{
person a[5]={person("a1",34),
person("a2",25),
person("a3",16),
person("a4",77),
person("a5",40)};
for(int i=0;i<5;i++)//排序
{
for(int j=i+1;j<5;j++)
if(a[j]<a[i]) swap(a[j],a[i]);
}
for(int i=0;i<5;i++)
cout<<a[i];
int fage;
cout<<"请输入要查找的年龄：";
cin>>fage;
person* p=bsearch2(a,5,fage);//查找
if(p!=NULL) cout<<*p;
else cout<<"未找到！
";
}