第4题

#include<iostream>
#include<string>
using namespace std;
class student{
public:	void account();
		static void account_count_sum_average();
		student(string name1,float score1);
private:string name;
		static float totai_score();
		static int count;
		static float sum;
		static float average;
		float score;

};
student::student(string name1,float score1)
{name=name1;
score=score1;
++count;
sum+=score;
average=sum/count;}
void student::account()
{cout<<"姓名："<<name<<endl;
cout<<"成绩："<<score<<endl;}
 void student::account_count_sum_average()
{cout<<"学生人数："<<count<<endl;
cout<<"累加成绩"<<sum<<endl;
cout<<"平均成绩："<<average<<endl;}
int student::count=0;
float student::sum=0.0;
float student::average=0.0;
int main()
{student stu1("dlh",100);
stu1.account();
student::account_count_sum_average();
student stu2("wy",90);
stu2.account();
student::account_count_sum_average();
return 0;}