设计一个多功能的MyTime类 代码参考

#include <iostream>
#include <cstdio>

using namespace std;

class MyTime
{
    private:
        int hour;
        int minute;
        int second;
    public:
        MyTime(){hour=0;minute=0;second=0;}
        MyTime(int,int,int);
        void Register(int,int,int);
        void Show_12();
        void Show_24();
        void Sub(int,int,int);
        void Add(int,int,int);
};

MyTime::MyTime(int a, int b, int c)
{
    hour=a;
    minute=b;
    second=c;
}

void MyTime::Show_12()
{
    if(hour>11)
    {
        printf("%02d:%02d:%02d PM
",hour-12,minute,second);
    }
    else
    {
        printf("%02d:%02d:%02d AM
",hour,minute,second);
    }
    return;
}

void MyTime::Show_24()
{
    printf("%02d:%02d:%02d
",hour,minute,second);
    return;
}

void MyTime::Sub(int a, int b, int c)
{
    hour-=a;
    minute-=b;
    second-=c;
    while(second<0)
    {
        second+=60;
        minute-=1;
    }
    while(minute<0)
    {
        minute+=60;
        hour-=1;
    }
    while(hour<0)
    {
        hour+=24;
    }
    return;
}

void MyTime::Add(int a, int b, int c)
{
    hour+=a;
    minute+=b;
    second+=c;
    while(second>59)
    {
        second-=60;
        minute+=1;
    }
    while(minute>59)
    {
        minute-=60;
        hour+=1;
    }
    while(hour>23)
    {
        hour-=24;
    }
    return;
}

void MyTime::Register(int a,int b, int c)
{
    hour=a;
    minute=b;
    second=c;
    return;
}

int main()
{
    MyTime one,two(8,10,30);
    int a,b,c,x,y,z;
    cin>>a>>b>>c>>x>>y>>z;
    one.Show_12();
    one.Show_24();
    two.Show_12();
    two.Show_24();
    one.Register(a,b,c);
    one.Add(x,y,z);
    two.Sub(x,y,z);
    one.Show_12();
    one.Show_24();
    two.Show_12();
    two.Show_24();
    return 0;
}