第四章作业4.21

#include<iostream>
#include<iomanip>
#include<string>
using namespace std;
class student{
private:
float score;
public:
string number;           //学生学号；
string name;             //学生姓名；
static int sum;          //学生总人数；
static float sumscore;   //学生总成绩；
static float aver;       //学生平均成绩；
void show();
static void count();
student(string n,string num,float s)
{
number=num;
name=n;
score=s;
++sum;
sumscore=sumscore+score;
aver=sumscore/sum;
}
};
int student::sum=0;
float student::sumscore=0;
float student::aver=0.0;

void student::show()
{
cout<<"姓名为:"<<name;
cout<<"   学号为:"<<number;
cout<<"的学生的成绩为:"<<score<<endl;
}
void student::count()
{
cout<<"学生总人数为："<<sum<<endl;
cout<<"学生总成绩为："<<sumscore<<endl;
cout<<"学生平均成绩为："<<aver<<endl;
}

int main()
{
student stu1("aaa","10000000",87),stu2("ddd","20000000",92),stu3("www","30000000",88),stu4("qqq","40000000",90);
stu1.show();
stu2.show();
stu3.show();
stu4.show();
cout<<endl;
student::count();
return 0;
}