第四章作业4.21



#include<iostream>
#include<string>
using namespace std;
class student{
public:
 student(string name1,float score1);
 void show();
 void show_count_sum();
private:
 string name;//学生姓名
 float score;//学生成绩
 static int count;//静态数据成员，用于统计学生人数
 static float sum;//静态数据成员，用于统计累加成绩
 static float ave;//静态数据成员，用于计算学生平均成绩
};
student::student(string name1,float score1)//定义构造函数
{
 name=name1;
 score=score1;
    ++count;
 sum=sum+score;
 ave=sum/count;
}
void student::show()
{
 cout<<"姓名："<<name<<endl;
 cout<<"成绩:"<<score<<endl;
}
void student::show_count_sum()
{
 cout<<"学生人数"<<count<<endl;
 cout<<"累加成绩"<<sum<<endl;
    cout<<"平均成绩"<<ave<<endl;
}
int student::count=0;
float student::sum=0.0;
float student::ave=0.0;
int main()
{
   student stu1("xiaoming",89);
   stu1.show();
   stu1.show_count_sum();
       student stu2("xiaohong",89);
    stu2.show();
    stu2.show_count_sum();
    return 0;
}