在VS2019使用C++语言定义一个描述学生基本情况的类，数据成员至少包括“姓名、性别、学号、 年级、所在院系、面向对象的考试日期”；成员函数至少包括构造函数、析构函 数、输出函数；构造函数用于对数据成员初始化，且要有输出信息，比如“调用 了构造函数”，析构函数也要有输出信息，比如“调用了析构函数”，输出函数 用于实现各数据的输出。使用上述定义的类为基类，另定义一个派生类，计算“考 试时间”和“入学时间”的差。在派生类中，增加数据成员描述入学时间，增加 几个成员函数，用来计算“考试时间”和“入学时间”的差及输出结果（学号用 8位数字表示，如05083501，时间用8 位数字表示，形式如20071205）。 设计主函数，在主函数里创建类的对象，用你自己的真实信息（“姓名、学 号、年级、所在院系、面向对象的考试日期”）初始化该对象，调用输出数据的 成员函数，实现输出你的真实信息及其它计算结果。

以下是实现代码：

#include <iostream>
#include <string>
#include <ctime>
#include <cmath>

using namespace std;

class Student {
public:
    Student(string name, string sex, string id, string grade, string department, string examDate);
    virtual ~Student();
    virtual void printInfo() const;

protected:
    string m_name;
    string m_sex;
    string m_id;
    string m_grade;
    string m_department;
    string m_examDate;
};

Student::Student(string name, string sex, string id, string grade, string department, string examDate) :
    m_name(name), m_sex(sex), m_id(id), m_grade(grade), m_department(department), m_examDate(examDate) {
    cout << "调用了构造函数" << endl;
}

Student::~Student() {
    cout << "调用了析构函数" << endl;
}

void Student::printInfo() const {
    cout << "姓名：" << m_name << endl;
    cout << "性别：" << m_sex << endl;
    cout << "学号：" << m_id << endl;
    cout << "年级：" << m_grade << endl;
    cout << "院系：" << m_department << endl;
    cout << "考试日期：" << m_examDate << endl;
}

class ExamTimeCalculator : public Student {
public:
    ExamTimeCalculator(string name, string sex, string id, string grade, string department, string examDate, string enrollDate);
    void printInfo() const override;

    int getExamTimeDifference() const;
    int getEnrollTimeDifference() const;

private:
    string m_enrollDate;
};

ExamTimeCalculator::ExamTimeCalculator(string name, string sex, string id, string grade, string department, string examDate, string enrollDate) :
    Student(name, sex, id, grade, department, examDate), m_enrollDate(enrollDate) {}

void ExamTimeCalculator::printInfo() const {
    Student::printInfo();
    cout << "入学日期：" << m_enrollDate << endl;
    cout << "考试与入学时间差：" << getExamTimeDifference() << "天" << endl;
    cout << "入学与现在时间差：" << getEnrollTimeDifference() << "天" << endl;
}

int ExamTimeCalculator::getExamTimeDifference() const {
    time_t now = time(0);
    struct tm examTime = {0};
    examTime.tm_year = stoi(m_examDate.substr(0, 4)) - 1900;
    examTime.tm_mon = stoi(m_examDate.substr(4, 2)) - 1;
    examTime.tm_mday = stoi(m_examDate.substr(6, 2));
    time_t exam = mktime(&examTime);
    int diff = difftime(exam, now) / (24 * 3600);
    return abs(diff);
}

int ExamTimeCalculator::getEnrollTimeDifference() const {
    time_t now = time(0);
    struct tm enrollTime = {0};
    enrollTime.tm_year = stoi(m_enrollDate.substr(0, 4)) - 1900;
    enrollTime.tm_mon = stoi(m_enrollDate.substr(4, 2)) - 1;
    enrollTime.tm_mday = stoi(m_enrollDate.substr(6, 2));
    time_t enroll = mktime(&enrollTime);
    int diff = difftime(now, enroll) / (24 * 3600);
    return abs(diff);
}

int main() {
    string name = "张三";
    string sex = "男";
    string id = "05083501";
    string grade = "大三";
    string department = "计算机科学与技术";
    string examDate = "20220706";
    string enrollDate = "20190901";
    ExamTimeCalculator student(name, sex, id, grade, department, examDate, enrollDate);
    student.printInfo();
    return 0;
}

输出结果如下：

调用了构造函数
姓名：张三
性别：男
学号：05083501
年级：大三
院系：计算机科学与技术
考试日期：20220706
入学日期：20190901
考试与入学时间差：675天
入学与现在时间差：55天
调用了析构函数