Question

我的课程时间可以显示时间，具体取决于一天中的静态变量小时数和一小时内的分钟数。我希望能够通过简单地更改我的静态变量来打印更新的时间。

在我的main（）中，我想基于默认的静态变量声明一些Time实例（一天24小时，一小时60分钟）。

Time a;
Time b(5);
Time c(61);

cout << "a = " << a << "\t";
cout << "b = " << b << "\t";
cout << "c = " << c << "\n";

// output is a =  0:00  b =  0:05 c =  1:01

Time::set_hr_in_day(60);

Time::set_min_in_hr(24);
cout << "a = " << a << "\t";
cout << "b = " << b << "\t";
//output should be a =  0:00    b =  0:05   c =  2:13

但是，代码仍会打印出默认静态变量的数字。

关于如何解决此问题的任何想法？顺便说一句，我正在尝试创建一个类来测试给定的驱动程序，因此更改我的主要功能不是一个选项。

以下是我的其余代码：

头文件

#ifndef TIME_H
#define TIME_H

#include <iostream>

using namespace std;

class Time {
private:
    int hour;
    int minute;
    static int dayhrs;
    static int hrsmin;

public:

    Time();
    Time(int min);
    Time(int hr, int min);
    Time(double hrs);
    int minutes() { return minute; };
    int hours() { return hour; };

    static void set_hr_in_day(int hr);
    static void set_min_in_hr(int min);
    static int dailyhr() { return dayhrs; };
    static int hourlymin() { return hrsmin; };

friend ostream& operator<<(ostream& os, const Time& t);


};



#endif

实施

#include "time.h"
#include <iostream>

using namespace std;

int Time::dayhrs = 24;//default
int Time::hrsmin = 60;

void Time::set_hr_in_day(int hr) {
    dayhrs = hr;
}

void Time::set_min_in_hr(int min) {
    hrsmin = min;
}


Time::Time() {
    hour = 0;
    minute = 0;
}

Time::Time(int min) {
    if (min > (Time::hourlymin() - 1)) {
        hour = min / Time::hourlymin();
        minute = min % Time::hourlymin();
    }
    else {
        hour = 0;
        minute = min;
    }

}

Time::Time(int hr, int min) {
    if (min > (Time::hourlymin() - 1)) {
        hour = min / Time::hourlymin() + hr;
        minute = min % Time::hourlymin();
    }
    else {
        hour = hr;
        minute = min;
    }

    if (hour > (Time::dailyhr() - 1))
        hour = hour % (Time::dailyhr());
}

Time::Time(double hrs) {
    double fraction = 0;
    fraction = hrs - (int)hrs;
    minute = fraction * Time::hourlymin();
    if (fraction * Time::hourlymin() - (int)(fraction * Time::hourlymin()) >= 0.5)
        minute += 1;
    hour = hrs - fraction;
    if (hour > (Time::dailyhr() - 1))
        hour = hour % (Time::dailyhr());
}



ostream& operator<<(ostream& os, const Time& t)
{
    if (t.minute > 9)
        os << t.hour << ":" << t.minute;
    else
        os << t.hour << ":0" << t.minute;
    return os;
}

驱动器

#include <iostream>
#include "time.h"

using std::cout;

int main() {
    cout << "*****************************************\n";
    cout << "Welcome to 'San Angel'!\n";
    cout << "[ 1 day = 24 hours, 1 hour = 60 minutes ]\n\n";

    Time a;
    Time b(5);
    Time c(61);
    Time d(47, 59);
    Time X(5.0);
    Time Y(1.5);
    Time Z(25.1);

    cout << "a = " << a << "\t";
    cout << "b = " << b << "\t";
    cout << "c = " << c << "\n";
    cout << "d = " << d << "\t";
    cout << "X = " << X << "\t";
    cout << "Y = " << Y << "\n";
    cout << "\t\tZ = " << Z << "\n";


    Time::set_hr_in_day(60);
    Time::set_min_in_hr(24);
    cout << "*****************************************\n";
    cout << "Welcome to the land of the remembered!\n";
    cout << "[ 1 day = 60 hours, 1 hour = 24 minutes ]\n\n";

    cout << "a = " << a << "\t";
    cout << "b = " << b << "\t";
    cout << "c = " << c << "\n";
    cout << "d = " << d << "\t";
    cout << "X = " << X << "\t";
    cout << "Y = " << Y << "\n";
    cout << "\t\tZ = " << Z << "\n";

return 0;

}
/**

OUTPUT:

*****************************************
Welcome to 'San Angel'!
[ 1 day = 24 hours, 1 hour = 60 minutes ]

a =  0:00   b =  0:05   c =  1:01
d = 23:59   X =  5:00   Y =  1:30
Z =  1:06
*****************************************
Welcome to the land of the remembered!
[ 1 day = 60 hours, 1 hour = 24 minutes ]

a =  0:00   b =  0:05   c =  2:13
d = 59:23   X = 12:12   Y =  3:18
Z =  2:18 */

Answer 1

您只在构造函数中执行计算。稍后修改静态变量时，不会自动重新计算结果。

一种可能的解决方案是将值存储在构造函数中，然后在写入流时进行实际计算。

如何通过更新静态变量来更新实例？

1 个答案: