我试图写一个C++程序，将显示一个12小时和一个24小时的时钟与改变分钟，小时和秒的能力。这两个时钟需要被显示的不一致，用“*"框，像这样：enter image description here
我相当有信心，时钟本身将运作，因为他们应该，但我不能让他们格式正确。
以下是我目前为止的代码：

#include <iostream>
#include <iomanip>
#include <ctime>

using namespace std;

// Function to create a string of a specified length with a specific character
string nCharString(size_t n, char c) {
    return string(n, c);
}

// Function to format a number as 2 digits, with a leading 0 if needed
string twoDigitString(unsigned int n) {
    if (n < 10) {
        return "0" + to_string(n);
    } else {
        return to_string(n);
    }
}

class TimeSim {
public:
    int hour;
    int minute;
    int seconds;
};

class hour_12_format : public TimeSim {
public:
    string meridian;
    hour_12_format() {
        time_t now = time(0);
        tm* ltm = localtime(&now);
        hour = ltm->tm_hour;
        minute = ltm->tm_min;
        seconds = ltm->tm_sec;
        if (hour >= 12) {
            meridian = "P M";
            hour -= 12;
        } else
            meridian = "A M";
    }

    void add_hour(int h) {
        hour += h;
        if (hour > 12) {
            hour -= 12;
            if (meridian == "A M") {
                meridian = "P M";
            } else if (meridian == "P M") {
                meridian = "A M";
            }
        }
    }

    void add_minute(int min) {
        minute += min;
        if (minute >= 60) {
            int h = minute / 60;
            minute -= 60 * h;
            add_hour(h);
        }
    }

    void add_seconds(int sec) {
        seconds += sec;
        if (seconds >= 60) {
            int m = seconds / 60;
            seconds -= 60 * m;
            add_minute(m);
        }
    }
};

class hour_24_format : public TimeSim {
public:
    hour_24_format() {
        time_t now = time(0);
        tm* ltm = localtime(&now);
        hour = ltm->tm_hour;
        minute = ltm->tm_min;
        seconds = ltm->tm_sec;
    }

    void add_hour(int h) {
        hour += h;
        if (hour >= 24) {
            hour -= 24;
        }
    }

    void add_minute(int min) {
        minute += min;
        if (minute >= 60) {
            int h = minute / 60;
            minute -= 60 * h;
            add_hour(h);
        }
    }

    void add_seconds(int sec) {
        seconds += sec;
        if (seconds >= 60) {
            int m = seconds / 60;
            seconds -= 60 * m;
            add_minute(m);
        }
    }
};

// Function to display the 12-hour clock within a rectangle
void display12HourClock(hour_12_format c1) {
    // Display rectangle
    int rectangleWidth = 26;
    string timeStr = twoDigitString(c1.hour) + ":" + twoDigitString(c1.minute) + ":" + twoDigitString(c1.seconds) + " " + c1.meridian;
    int padding = (rectangleWidth - timeStr.length()) / 2;

    cout << nCharString(rectangleWidth, '*') << endl;
    cout << "*   12-Hour Clock: " << nCharString(padding, ' ') << timeStr << nCharString(padding, ' ') << "   *\n";
    cout << nCharString(rectangleWidth, '*') << endl;
}

// Function to display the 24-hour clock within a rectangle
void display24HourClock(hour_24_format c2) {
    // Display rectangle
    int rectangleWidth = 26;
    string timeStr = twoDigitString(c2.hour) + ":" + twoDigitString(c2.minute) + ":" + twoDigitString(c2.seconds);
    int padding = (rectangleWidth - timeStr.length()) / 2;

    cout << nCharString(rectangleWidth, '*') << endl;
    cout << "*   24-Hour Clock: " << nCharString(padding, ' ') << timeStr << nCharString(padding, ' ') << "   *\n";
    cout << nCharString(rectangleWidth, '*') << endl;
}

int main() {
    hour_12_format c1;
    hour_24_format c2;
    int choice = 0;
    while (choice != 4) {
        display12HourClock(c1);
        display24HourClock(c2);

        cout << "\n\n*************************\n";
        cout << "* 1 - Add One Hour\t*\n";
        cout << "* 2 - Add One Minute\t*\n";
        cout << "* 3 - Add One Second\t*\n";
        cout << "* 4 - Exit Program\t*\n";
        cout << "*************************\n";

        cout << "Enter your choice: ";
        cin >> choice;

        switch (choice) {
        case 1:
            c1.add_hour(1);
            c2.add_hour(1);
            break;
        case 2:
            c1.add_minute(1);
            c2.add_minute(1);
            break;
        case 3:
            c1.add_seconds(1);
            c2.add_seconds(1);
            break;
        case 4:
            exit(0);
            break;
        default:
            cout << "Enter Correct Choice!!\n";
            break;
        }
    }

    return 0;
}

字符串
这就是我的输出结果：

**************************
*   12-Hour Clock:        08:23:55 P M          *
**************************
**************************
*   24-Hour Clock:          20:23:55            *
**************************

*************************
* 1 - Add One Hour  *
* 2 - Add One Minute    *
* 3 - Add One Second    *
* 4 - Exit Program  *
*************************

型
我试着调整每一条线，但没有运气，也不知道我错在哪里。