面向对象程序设计测试

#include <iostream>
#include<iomanip>
using namespace std;
class Point
{
    protected:
    double x,y;
    public:
    Point(double a = 0,double b = 0):x(a),y(b) {
        cout << "Point constructor called\n";
    };
    ~Point () {
        cout << "Point destructor called\n";
    };
};
class Circle
{
    protected:
    Point p1;
    double r;
    public:
    Circle(double a = 0,double b = 0,double c = 0):p1(a,b),r(c) {
        cout << "Circle constructor called\n";
    };
    ~Circle () {
        cout << "Circle destructor called\n";
    };
    double getCircumference() {
        return 2*3.14*r;
    }
};

int main()
{
    float x,y,r;
    cin>>x>>y>>r;
    Circle c(x,y,r);
    cout<<fixed<<setprecision(2)<<c.getCircumference()<<endl;
    return 0;
}

#include <iostream>
#include <iomanip>
#include <string>
using namespace std;
class Person
{
    protected:
    string name;
    int age;

    public:
    Person() : name("person"), age(0){};
    Person(string p_name, int p_age) : name(p_name), age(p_age){};
    void display() { cout << name << ":" << age << endl; }
};
class Student : public Person
{
    protected:
    int ID;
    float cpp_score;
    float cpp_count;
    float cpp_grade;

    public:
    Student(string n,int a,int sid,float score,float count):Person(n,a),ID(sid),cpp_score(score),cpp_count(count) 
    {
        cpp_grade = cpp_score * 0.9 + cpp_count * 2;
    };
    void print()
    {
        cout << ID << " " << name << " " << setiosflags(ios::fixed) << setprecision(1) << cpp_grade << endl;
    }
}; 
int main()
{
    while (1)
    {
        string name;
        int sid,age;
        float score,count;
        cin >> name;
        if (name == "0")
            exit(0);
        cin >> sid >> age >> score >> count;
        Student s1(name,age,sid,score,count);
        s1.print();
    }
}

#include <iostream>
#include <iomanip>
#include <string>
using namespace std;
class Person
{
    protected:
    string name;
    int age;

    public:
    Person() : name("person"), age(0){};
    Person(string p_name, int p_age) : name(p_name), age(p_age){};
    void display() { cout << name << ":" << age << endl; }
};
class Student : public Person
{
    protected:
    int ID;
    float cpp_score;
    float cpp_count;
    float cpp_grade;

    public:
    Student(){};
    Student(string n,int a,int sid,float score,float count):Person(n,a),ID(sid),cpp_score(score),cpp_count(count) 
    {
        cpp_grade = cpp_score * 0.9 + cpp_count * 2;
    };
    void print()
    {
        cout << ID << " " << name << " " << setiosflags(ios::fixed) << setprecision(1) << cpp_grade << endl;
    }
    float getGrade()
    {
        return cpp_grade;
    }
}; 
class Teacher : public Person
{
    protected:
    int ID;
    Student stu[100];
    int count;
    float cpp_average;
    public:
    Teacher(string n,int a,int tid):Person(n,a),ID(tid),count(0),cpp_average(0){};
    void Add (Student & stu1)   {
        stu[count] = stu1;
        count++;
    }
    void average() {
        float sum = 0;
        for (int i = 0; i < count; i++)
        {
            sum += stu[i].getGrade();
        }
        cpp_average = sum / count;
    }
    void print() {
        cout << ID << " " << name << " " << count << " " << setiosflags(ios::fixed) << setprecision(1) << cpp_average << endl;
        for (int i = 0; i < count; i++)
        {
            stu[i].print();
        }
    }
};

int main()
{
    string name;
    int age;
    int ID;
    float cpp_score;
    float cpp_count;
    cin >> name >> ID >> age;
    Teacher t(name, age, ID);
    while (1)
    {
        cin >> name;
        if(name == "0") {
            break;
        }
        cin >> ID >> age >> cpp_score >> cpp_count;
        Student s(name, age, ID, cpp_score, cpp_count);
        t.Add(s);
    }
    t.average();
    t.print();
}

神奇，这些题用float就能过，用double就过不了。