对象数组 运用指针排序

#include<iostream>
using namespace std;
class student{

 long number;
 public :
     student(long number):number(number){}
     long showme(){return number;}
     student();
};
student::student(){}
int main(void)
{
     student b[5]={student(10001),student(10004),student(10005),student(10003),student(10002)};
     student *a=b;  //！！！！！！！！！！建立一个指向对象数组的指针           student *a=new student[5];

  //  student a[5]={student(10001),student(10004),student(10005),student(10003),student(10002)};
    for(int i=0;i<4;i++)
    {
      int j=i;
       for (int k=j+1;k<5;k++)
       {
           student middle;
          // student middle;
           if((a+k)->showme()>(a+j)->showme())
           // if(a[k].showme()>a[j].showme())
                  j=k;
            middle=*(a+j);
           *(a+j)=*(a+i);
            *(a+i)=middle;
         //    middle=a[j];
         //  a[j]=a[i];
          //  a[i]=middle;
       }

    }
    for(int i=0;i<5;i++)
    {
        cout<<(a+i)->showme()<<endl;
        //cout<<a[i].showme()<<endl;
    }

    return 0;
}