用多文件组织多个类的程序

#include<iostream>
using namespace std;
class Time
{
public:
    Time(int=0,int=0,int=0);
    void show_time( ); //根据is_24和from0，输出适合形式-20:23:5/8:23:5 pm/08:23:05 pm
    void add_seconds(int); //增加n秒钟
    void add_minutes(int); //增加n分钟
    void add_hours(int); //增加n小时
    static void change24();  //改变静态成员is_24，在12和24时制之间转换
    static void changefrom0();   //改变静态成员from0，切换是否前导0
private:
    static bool is_24; //为true时，24小时制，如20:23:5；为flase，12小时制，显示为8:23:5 pm
    static bool from0; //为true时，前导0，8:23:5显示为08:23:05
    int hour;
    int minute;
    int sec;
};
bool Time::is_24=true;
bool Time::from0=false;
Time::Time(int h,int m,int s)
{
    hour=h;
    minute=m;
    sec=s;
}
void Time::change24()
{
    is_24=!is_24;
}
void Time::changefrom0()
{
    from0=!from0;
}
void Time::show_time( )
{
    int h=hour%12;
    if(is_24&&!from0)
        cout<<hour<<":"<<minute<<":"<<sec<<endl;
    else if(is_24&&from0)
        cout<<(hour<10?"0":"")<<hour<<":"<<(minute<10?"0":"")<<minute<<":"<<(sec<10?"0":"")<<sec<<endl;
    else if(!is_24&&from0)
        cout<<(h<10?"0":"")<<h<<":"<<(minute<10?"0":"")<<minute<<":"<<(sec<10?"0":"")<<sec<<" "<<((hour<12)?"am":"pm")<<endl;
}
void Time::add_seconds(int n)
{
    sec=sec+n;
    if(sec>59)
        add_minutes(sec/60);
    sec=sec%60;
}
void Time::add_minutes(int n)
{
    minute=minute+n;
    if(minute>59)
        add_hours(minute/60);
    minute=minute%60;
}
void Time::add_hours(int n)
{
    hour=hour+n;
    if(hour>24)
        hour=hour%24;
}
int main( )
{
    cout<<"二十四小时制，不前导0："<<endl;
    Time t1(23,14,25),t2(8,45,6);
    cout<<"t1是:";
    t1.show_time();
    cout<<endl;
    cout<<"t2是:";
    t2.show_time();
    cout<<endl;
    t1.add_hours(10);
    t2.add_hours(10);
    cout<<"10小时候，切换是否前导0:"<<endl;
    Time::changefrom0();
    cout<<"t1是:";
    t1.show_time();
    cout<<endl;
    cout<<"t2是:";
    t2.show_time();
    cout<<endl;
    Time::change24();
    cout<<"换一种制式:"<<endl;
    cout<<"t1是:";
    t1.show_time( );
    cout<<endl;
    cout<<"t2是:";
    t2.show_time( );
    cout<<endl;
    return 0;
}